Reproduction - The Genes

This means you will have plenty of time to get to know your creatures and to teach them about life before they become parents and you have to start worrying about children running around all over the place! Many animals are capable of breeding before they reach their full size, and the creatures created by the Shee are no exception. This allows them to have enough children to keep the race alive in the harsh environments that they used to live in.

Organs
There are two organs involved in breeding and the reproductive system the gonad organ and the uterus organ. Males do not have a uterus organ (even though they carry the genes, these genes are not expressed in male creatures) but both sexes have a gonad organ.

The uterus controls various aspects of pregnancy in female creatures such as when they lay their eggs, how long they stay pregnant for and whether they return home (or try to) to lay their eggs.

The gonad controls all of the hormonal changes a creature goes through during puberty and regulates the fertility cycle in males and females once they are adult.

Apart from the genes controlling the biochemical angle of the reproduction, there are also some behavioural genes involved instincts for mating and egg-laying, and stimuli to give the metabolism of the creature some feedback. There are even genes that change the gait of any creature looking for a mate! Reproduction is not just about chemicals after all

A full list of the genes involved in breeding can be found at the end of this article.

Hormones
Oestrogen (chemical 46) This hormone is found only in female creatures and controls their fertility cycle. Once a girl gets to her youth, her reproductive genes switch on, and she goes through puberty. This involves her gonad beginning to produce the hormone oestrogen and emit it into her system. To start with, there is not enough oestrogen to make her fertile, and she will not be able to have children of her own straight away. Over the course of a few minutes though, her oestrogen levels will build up until she does become fertile.

Testosterone (chemical 53) This is the male equivalent of oestrogen and is found only in male creatures. When a lad gets to youth, his reproductive system also turns on and starts to pump out the hormone testosterone. Like girls of the same age, he is not fertile straight away, but his reproductive system is much less complicated than a girls, and so he reaches a breeding condition slightly earlier.

Libido lowerer (chemical 40) This is an inhibitory reproductive hormone the opposite of oestrogen and testosterone that encourage breeding. Libido lowerer is emitted by the reproductive system during those periods of time when a creature is not fertile during their puberty, during pregnancy, and during those parts of their reproductive cycle that the levels of oestrogen and testosterone are too low to lead to a successful mating. It reacts with the other hormones (Arousal potential and Sex drive) to reduce their effect and remove them from the bloodstream during these periods, but as soon as things are back to normal, the emission of Libido lowerer stops again.

1 Arousal Potential + 1 Libido lowerer => 1 Libido lowerer
1 Sex drive + 1 Libido lowerer => 1 Libido lowerer

Arousal potential (chemical 39) A chemical signal that a creature is fertile and ready to reach breeding condition. There is a slight lag between a creature being fertile and mating; this allows them time to find a suitable partner and helps to stop them from being single-minded breeding machines!

In a female creature, Arousal potential is emitted as soon as the I am fertile locus is switched on that is, once the level of oestrogen has reached a level suitable for breeding. Arousal potential first reacts with any Libido lowerer in her system and removes it, and then begins to build up. When she meets a suitable male, Opposite sex pheromone will be injected into her system, and react with the Arousal potential already there to produce Sex drive. At this point, her instincts will take over and encourage her to push the male. It is at this point that the male receives his first dose of Arousal potential males do not produce this hormone themselves, but only receive it through a stimulus when a female pushes them.

1 Arousal potential + 1 Opposite Sex pheromone => 1 Sex drive

Opposite sex pheromone (chemical 41) This is a special chemical called a pheromone a hormone that can travel through the air between two creatures and acts as a signal. When a female creature sees a male creature or vice versa and they are both in breeding condition then this chemical is released by both of them to encourage them to get together. It reacts with Arousal potential to produce sex drive the only chemical out of all of this lot that is visible to the brain!

1 Arousal potential + 1 Opposite sex pheromone => 1 Sex drive

Progesterone (chemical 48) The pregnancy chemical. This chemical is emitted in females when their I am pregnant locus is activated by a successful mating. To begin with it builds up very slowly as it reacts with any oestrogen left in her system, but after this is builds up and causes other effects, such as pregnancy sprites to be used (swollen tummy sprites used to indicate a pregnant female). Once the female has laid her egg, the locus is switched off again, and the emission of progesterone stops. The last of the progesterone will decay naturally out of her system, while the oestrogen that is now being emitted again will go on to re-establish the fertility cycle.

1 Oestrogen + 1 Progesterone => 1 Progesterone

Comfort (chemical 162) Another drive, used usually in pregnancy to help females navigate their way home to lay their eggs in safety. This drive is emitted in females when their I am pregnant locus is activated by a successful mating. It is a drive chemical, and so the brain is able to make decisions based on the level of the chemical. Instincts tell the female to go home if she has a high Comfort drive level this is to try and make sure that eggs are laid in the safety of the home terrarium on the Shee ship. Once the creature has reached home (a small smell emitter inside each terrarium) then her levels of comfort are reduced by a stimulus. Laying her egg will also reduce her Comfort drive levels to zero.

Sex drive (chemical 161) All of the previous chemicals are hormones, and though they can provoke a great deal of biochemical changes and even behavioural ones dancing, egg-laying and so on this is the only reproductive chemical that a creature can base decisions on. In short if sex drive is high, then go look for someone to mate with! Sex drive is the last chemical created in the long chain that leads to mating, and so whenever it is high, you know that your creature is really fertile.

Behaviour and stimuli
Tickling The natural action of a creature that is ready to mate is to find a member of the opposite sex and push them. If the pushee is not ready to mate perhaps they are too young, or perhaps their sex drive is not high enough then instead of a mating action, they will get tickled instead!

Dancing Some Norns (most of the new breeds in Docking Station for example) dance when they are feeling friendly. This is partly to attract their owners attention but also serves to advertise how they feel to any other Norns out there that feel the same. The gait is reliant on the amount of sex drive in the Norn, so if one of your Norns suddenly starts to do an odd little shuffle-shuffle-stomp-foot tap, then they are probably looking for a mate.

Kiss-popping If you hear a prolonged squeaky kisssssssss POP! then you have just heard your creatures mating. Apparently the Shee were very easily embarrassed and so designed their creatures in such a way that mating was extremely discrete. During the kisspop, a female receives sperm from a male which fertilises her egg at which point she becomes pregnant.

Obsessive mating Occasionally you may have a problem with a pair of creatures they just wont stop trying to mate! All living creatures have a deep drive to reproduce themselves as soon and as often as possible, and creatures are no different. Usually, each mating attempt will make the creatures concerned tired so that they may need to sit down and have a rest afterwards, but sometimes the good feelings just outweigh the tiredness and they keep going.

Homing instinct Some female creatures have an instinct to lay their eggs in a place they know is safe or should be. During their pregnancy, a chemical called Comfort or Homesickness is created and the level rises throughout the pregnancy. As it rises, it prompts restless behaviour and eventually the female decides to set off home. Inside each terrarium on the Shee ship is a small device that acts as the home spot.

Squatting Creature eggs are quite soft when they are laid, and so if they fell onto the floor too hard they would get broken. Female creatures generally squat down for a brief time while they lay their egg so that it is set down gently on the floor. Egg laying is an involuntary action, which means that the creature has no choice in deciding whether to do it or not! However, things are not rigidly forced; the creature will only carry out the involuntary action once they have nothing else to do they will go on to complete any action they have decided to carry out first.

Engine and loci
Essentially the genome manipulates levels of hormones within a creature in order to turn on and off various engine loci that relate to breeding. The three loci used are

I am fertile This locus is inactive by default which means that something has to happen inside your creatures before they are able to mate. Currently, this locus is activated by receptors that track the levels of oestrogen (in females) and testosterone (in males) and switches the locus on once these levels have reached a certain minimum threshold.

Receptive to sperm if >0 Turning on the first locus is only the first step in activating the reproductive system. A second layer of regulatory hormones has to be negotiated in order to generate sex drive and stimulate mating to take place. Once the creature is fertile, this second layer of complexity is kicked off as additional hormones are emitted, behaviour (such as pushing members of the opposite sex) is encouraged and so on. Hopefully all of this behaviour will result in a creature that is primed to mate and that will hopefully have a successful outcome of that mating. At this point (when sex drive is high enough), the receptive to sperm locus is activated (in female creatures only) and any matings at this point are likely to be successful.

I am pregnant It is fairly obvious what this locus refers to! After mating, if the female has been successfully fertilised, then her I am pregnant locus will be activated and a change in her reproductive biochemistry will be kicked off, helping her to maintain her pregnancy. After she has laid her egg, the locus is inactivated again, and her reproductive system will start to ready her for the next potential mating opportunity.

Pregnancy
After a successful mating, a locus is turned on inside the female that changes her status from Ready to conceive to I am pregnant. An emitter begins to pump progesterone into her system to keep her pregnant and this also has a knock-on effect on several other chemicals. Progesterone reacts with oestrogen to remove it from the system totally. As the level of oestrogen falls and the progesterone rises, the metabolism realises that the creature is no longer fertile and starts to produce libido lowerer again to reinforce that.

1 Oestrogen + 1 Progesterone => 1 Progesterone

The presence of progesterone in the female even has an effect on her sprites her stomach will visibly swell as the engine adds a new set of sprites to her body to indicate her condition. After birth the level of progesterone will fall and as it does her body will return to normal.

Another chemical that is emitted in some creatures during pregnancy is a drive chemical called Comfort or Homesickness (either name is ok to use). This drive ties to an instinct that some females have to return home to lay their eggs - once the drive reaches a high level, then the female will try to navigate home so that her egg can be laid in a safe spot.

A pregnant female may also complain more of being hungry. Being pregnant does not take very much out of a female creature it is not long enough to be a major drain on her physical resources but it will probably make her a bit more hungry and tired than usual. Make sure that she has plenty of good food to eat and peace and quiet to rest (and lay her egg) in.

Birth and recovery
Finally, the egg inside the female grows to a size where it can be laid and develop on its own. Once the level of progesterone inside the female gets to a certain level (0.875), then an involuntary action (Invol 1) is triggered. Unlike normal decisions that creatures make themselves, involuntary actions are acts they have to take, but only when they are not actively engaged in doing something else. If the female is on her way to find food for example, she will complete that action first before carrying out an involuntary action.

However it happens, there comes a time when that egg has to be laid. A female has a set of special poses where she crouches down and pop, out comes that egg. Females usually spend a few minutes resting after laying, but then go off in search of food, excitement and distraction just as normal. The egg can be safely left to hatch in its own time or taken to an incubator or heat pad to speed up hatching.

After the birth of her egg, the female is still full of progesterone left over from her pregnancy. Although this will eventually decay away to nothing, the female is entirely infertile for the entire period. What happens is that as she lays the egg, her I am pregnant locus is turned off and so the engine registers her as being not pregnant, but not fertile either. At this stage, her oestrogen emitter will kick in and start to pump out quantities of oestrogen again to bring her back up to the fertile level.

However oestrogen and progesterone react together, so at first all of the newly emitted oestrogen will react with the excess progesterone until it is removed from the system (by stimulus and natural decay) at which point the oestrogen can slowly build up again to a fertile level, and the whole process can start again.

This effect allows a female a short period after laying her egg in which to be infertile and escape from all the attention!

Genes involved
This list of genes is taken from a Generation 1 (straight out of the box) Norn. Including all of the peripheral genes that code for behaviour instincts, stimuli, gaits and even poses reproduction ties up approx 52 genes.

Organ : UTERUS
Present in both genders, expressed only in females
This organ gene is expressed only in female creatures, but is also carried by the male. It holds genes relating to pregnancy and egg-laying and can be killed by Antigens 1 and 0. It also suffers from damage if exposed to radiation (heavy metal).

Emitter: Go Home to lay eggs
Digital emitter, expressed only in females
This emitter is tied to the I am pregnant locus. As soon as a female Norn is pregnant, this locus switches from 0 to 1, and the emitter pumps out 1.0 Comfort drive. As this chemical is a drive, the creature can then make a decision as to whether to go home or not to lay her eggs, based on her instincts.

Emitter : Progesterone
Digital emitter, expressed only in females
This emitter is also tied to the I am pregnant locus. Once the female is pregnant and the locus is set to 1, this emitter will pump out progesterone at a rate of 0.012 units of progesterone every tick until the locus is deactivated by the female laying an egg.

Receptor : Lay eggs (Invol 1)
Digital receptor, expressed only in females
This receptor tracks the level of progesterone in the creature and when the level is high enough sends a message to the creature to lay her egg. The action of laying an egg is involuntary the creature does not have to decide to lay, but is forced to by her metabolism. Involuntary actions are queued up in the brain and acted on whenever no other decision is being acted on this might delay the laying of an egg until the creature has finished eating for example.

The level of progesterone must reach 0.875 before the action is triggered. If you would like pregnancy to be longer, simply set this value to be higher.

Organ : GONAD
Present and expressed in both genders
This organ is expressed in both male and female creatures and holds the genes responsible for creating fertility cycles and regulating sex drive. This organ is damaged by Antigens 2 and 3, and also suffers damage from radiation. Several genes in here also regulate the degree of mutation that will be applied to the genome of any offspring during conception.

Emitter : Oestrogen
Digital emitter, expressed in females only
This emitter takes its cues from the I am fertile (egg/sperm ready) locus in the engine and acts in concert with the Oestrogen receptor to regulate fertility in females. The locus is switched from 0 to 1 when the receptor finds enough oestrogen in the Norn; this emitter keeps on pumping out oestrogen if the level is below the fertile threshold.

The emitter is set to pump out oestrogen if the levels in the female are lower than 0.62. if this is the case, then the emitter will emit 0.012 units of oestrogen at intervals of 2 ticks. This is a digital emitter, so as soon as the level rises above the threshold of 0.62, the emitter stops emitting; similarly as soon as the level falls below 0.62, it will start emitting.

Receptor : Oestrogen
Analogue receptor, expressed only in females
This receptor partners the emitter as above in the sense that their behaviour regulates the oestrogen level, and hence the fertility of a female. This receptor is not digital, but analogue, which has the result of softening the way the receptor works. It is tied to the Become fertile if high locus in the engine and tracks the level of oestrogen in the female. As the level rises above 0.196, the receptor is activated and starts to turn on the I am fertile locus. Because it is an analogue receptor, the locus is not turned fully on immediately, but is turned on proportional to the oestrogen level itself if the oestrogen level is only 0.2, then the locus is barely on at all, but if the level of oestrogen rises to 0.7, then the locus would be fully on. it is this that gives the females a slowly undulating fertility cycle, with periods of infertility and maximum fertility.

The receptor turns on the I am fertile locus the locus that the emitter reads from. If the receptor can detect a lot of oestrogen, this locus is tuned on and so the emitter is turned off. If the level of oestrogen drops below the threshold of the receptor, then the locus is turned off and the emitter then begins to emit oestrogen again.

Emitter : Libido lowerer
Digital emitter, expressed in both genders
Getting the creatures metabolism ready to bear children is a long process of chemical cascades, and it is important that the system is fully ready for kids before the creatures start to try mating or else they might not do anything else! To prevent mass kiss-popping orgies, inhibitory hormones are emitted during those phases of the creatures cycle where they are not fertile, and these hormones prevent any sort of mating behaviour being activated during those periods.

Libido lowerer is emitted in both males and females during those times when the I am fertile locus is inactive. This is not so often in males, but females have a much clearer cyclic fertility, and of course are also technically infertile during pregnancy (in that they cannot become any more pregnant than they already are!). The libido lowerer reacts not with the primary (fertility) sex hormones, but with additional (regulatory) sex hormones arousal potential and sex drive itself. If these are created by accident, or are hanging around in the creatures system as the creature becomes infertile, then libido lowerer will immediately be emitted and mop up any traces of hormone. When it emits, 0.051 units of Libido lowerer are emitted every 2 ticks.

1 Arousal Potential + 1 Libido lowerer => 1 Libido lowerer
1 Sex drive + 1 Libido lowerer => 1 Libido lowerer

Emitter : Arousal potential
Digital emitter, expressed only in females
Once fertility has been established, the next stage of reproduction is to generate an urge to mate. In female creatures only, once the I am fertile locus is active that is, the level of oestrogen is high enough to have turned the locus on then an additional emitter begins to emit a hormone called Arousal potential. This is emitted at a rate of 0.055 units every 3 ticks once the locus level is more than 0.502.

Arousal potential puts the females into a receptive state, ready to mate when the situation arises. Arousal potential reacts with another hormone, Opposite sex pheromone, produced when a female smells a male creature around and the result of this reaction is sex drive.

1 Arousal potential + 1 Opposite sex pheromone => 1 Sex drive

Emitter : Testosterone
Digital emitter, expressed only in males
So what is going on inside the male creatures all this time? In Creatures 3, the males have a much easier metabolism to deal with when it comes to reproduction. Where a female emits oestrogen, males emit testosterone. This emitter is tied to the I am fertile locus, and while the locus is inactive, this gene will emit testosterone at a rate of 0.02 every 4 ticks. The threshold level for the emitter is 0.502 if the level of the locus is lower than that, then the emitter is active.

Receptor : Testosterone
Analogue receptor, expressed in males only
This receptor partners the emitter above to create a cyclic fertility for males. The cycle is not as pronounced as that of females males spend only a small amount of time being infertile. They also obviously do not become pregnant, so can breed more frequently than females over the course of their life.

This receptor is also tied to the fertility locus, tuning it on (making the male fertile) if the level of testosterone rises above 0.188. As an analogue receptor, the higher the level rises above the threshold, the more the locus is turned on. Between the two of them , the level of testosterone and the degree of fertility of male creatures is kept within a narrow zone but still able to fluctuate slightly.

Emitter : Opposite sex pheromone
Digital emitter, expressed in both genders
Opposite sex pheromone is released into a creatures system when the brain recognises a creature of the opposite sex approaching. The gene is linked to a neurone in the situation lobe of the brain which can distinguish between male and females of the same species and when the neurone fires, Opposite sex pheromone is released at a rate of 0.055 units of pheromone every 3 ticks.

In females, this release triggers the creation of sex drive if they are currently fertile (by reacting with Arousal potential). In males, the pheromone is neutral until they have had a mating solicitation from a female.

Receptor : Sex drive
Digital receptor, expressed in females only
This receptor monitors the level of sex drive within a female. As the level rises, the female becomes receptive to sperm from the male and at this point if she mates, she will become pregnant. Once the level of sex drive rises above 0.188, any mating attempt may result in pregnancy.

*Receptor : Arousal potential
Digital receptor, expressed in males only
While a female begins to emit Arousal potential internally once she becomes fertile, males do not emit arousal potential at all. The only source of this hormone in males is through a stimulus that indicates that a female has tried to mate with them. The system was engineered this way in an attempt to prevent excessive mating; only females generate sex drive internally when fertile males have to be solicited by a female before they become interested in mating. Creatures are furry feminists!

The system takes advantage of a new gene interaction in Creatures 3 the ability to control the rate of a reaction using a receptor (more or less using the receptor to catalyse the reaction). This gene works in tandem with the reaction gene below to remove sex drive from a male unless he is in a situation where mating may be profitable ie there is a fertile female giving him a hello big boy look.

If the level of Arousal potential (injected into a male via the stimulus I have been pushed by a female) is lower than 0.31 units, then the attached reaction breaks down any resulting sex drive that might be generated. This is yet another way of keeping the kiss-popping to acceptable levels!

*Reaction : Sex drive inhibition
Expressed in males only
This reaction breaks down Sex drive totally inside males if the level of arousal potential falls below 0.31 units.

*Reaction : Libido lowerer destroys arousal potential
Expressed in both genders
This reaction removes any excess Arousal potential from a creature while it is in a period of infertility such as pregnancy, being too young or during normal cyclic infertility periods. The presence of Libido lowerer in itself indicates infertility, but Arousal potential may be left over from a fertile period. This reaction mops that up so that the creature is not distracted by trying to mate unsuccessfully.

1 Libido lowerer + 1 Arousal potential => 1 Libido lowerer

Reaction: destroy arousal potential when infertile
Expressed in both genders
In a way similar to the reaction above, a creature may be infertile yet still have hormones present in their bloodstream. This can be confusing to the player and the creature, who may continue to try mating even though they have no chance of success. To prevent this situation, reactions remove the regulatory (although obviously not the primary) sex hormones from the blood. This reaction removes any arousal potential from the blood of both sexes.

1 Arousal potential + 1 Libido lowerer => nothing.

Reaction: Sex drive reduction
Expressed in both genders
This is yet another reaction that removes regulatory hormones from the bloodstream of infertile creatures. In this case Sex drive is reduced probably more important than any other chemical, as it is this drive chemical that may cause creatures to make decisions to mate at inappropriate times and that lead to confusion later.

1 Sex drive + 1 Libido lowerer => 1 Libido lowerer

Reaction : Sex drive creation
Expressed in both genders
This reaction is the final step in the chemical cascade that prepares creatures for a successful mating. Their levels of primary hormones oestrogen and testosterone are high. The female has emitted Arousal potential and has found her mate, and reactions inside her have generated Sex drive, she pushes her chosen mate, injecting him with Arousal potential. This allows him to generate his own Sex drive and then instinct takes over, leading to mating and hopefully pregnancy.

Sex drive is the only chemical in the entire process which is apparent to the brain, and so is the only chemical that a creature can make decisions based upon. It is a drive, and so instincts suggest actions (mating) that will reduce the drive. Stimuli provide feedback to the metabolism after mating.

1 Arousal potential + 1 Opposite sex pheromone => 1 Sex drive

Reaction : Maintain pregnancy
Expressed in females only
When a female is fertile, she emits oestrogen. When she is pregnant, she emits progesterone. When going between each state, the two hormones react together, but the one that is being emitted wins out, clearing the system of the unwanted hormone. When a female has laid her egg then, natural chemical decay will soon remove all of the now unnecessary progesterone from her blood because none is emitted to replace it. Similarly, when a female falls pregnant, the progesterone that is emitted will remove all of the oestrogen from her bloodstream by reaction until the point where no more is emitted.

1 Progesterone + 1 Oestrogen => 1 Progesterone

Progesterone is used to indicate a state of pregnancy, and has knock-on effects on behaviour and sprites.

Half lives gene
Expressed in both genders
This gene is vitally important to any creature it determines the length of time a chemical takes to decay to nothing inside a creature. This helps to balance things out a bit for example, progesterone will slowly decay out of a female once she has laid her egg, allowing her to re-establish her fertility cycle.

Half lives for reproductive chemicals are measured in milliseconds, seconds and minutes. The gene has a slider that controls the setting of the time limit for decay the slider values are given in brackets after the time value:

Receptor : Start dancing (14)
Expressed in males only (DS and Add-on Norns only)
This gait receptor tracks the level of arousal potential in the male, and changes his gait to a dancing one when he is ready to mate. The threshold is 0.176 units of Arousal potential.

Receptor: Start jiving (15)
Expressed in females only (DS and Add-on Norns only)
This gait receptor tracks the level of Arousal potential in females and changes their gait to a jiving one when levels of Arousal potential reach 0.176 units or more.

Receptor : Sexy gait (13)
Expressed in both genders in C3 Norns
This is yet another receptor for a gait gene but tracks Sex drive itself this time. With the new reproductive system in Creatures 3, males and females may often be fertile, but not receptive. This gait receptor turns on the gait to indicate that a creature is ready to mate. In Docking Station, things changed a bit with creatures dancing as part of their courtship as well as when soliciting a mating!

Gait : Dancing (male)
Expressed in males only (DS and Add-on Norns only)
This is the gait switched on by the Start dancing receptor above. It contains poses that form an animation of some very bad dancing in males that are ready to mate.

Gait : Jive (Female)
Expressed in females only (DS and Add-on Norns only)
This is the female-only gait switched on by the Start jiving gait receptor above. The poses it refers to form an animation of some limited dancing that females can do to indicate their readiness to mate.

Instinct : Mating instinct
Expressed in both genders
This gene is an in-born instinct in creatures to find a member of the opposite sex and push them when their sex drive is high. The gene is activated at the youth lifestage, and so will not be active straight away the creature will need to sleep and dream first to process the instinct and make the brain connections relevant to the behaviour.

Instinct : Go Home if need for Comfort
Expressed in females only
This instinct is for females only, and directs them to go to their home base (following the smell of home) when they are pregnant. This is intended to make sure their eggs are laid in a suitable, safe environment. Comfort drive is usually only found in pregnant female creatures. Inside each terrarium on the Shee ship is a small emitter that is home. Once the female reaches that point, they can relax and lay their egg.

Pose genes (6 Dance gait genes, 5 jive gait genes, 4 egg lay genes, 4 horny scuttle genes)
Expressed variously
There is no need to list all of the pose genes individually each pose gene refers to a single pose that dictates how the creature should be standing (which way their head should face, how their arms are held, how their legs are posed, what their tail is doing and so on). when taken together, these poses form an animation that is called a gait. Specific gaits can be activated according to certain biochemical levels using receptors.

The dance, jive and horny scuttle genes refer to animations that creatures perform as part of their pre-mating courtship, while the lay egg poses are used only by females when laying their eggs.

Stimulus : Laid egg (Invol 1)
Expressed in females only
This stimulus is passed to a female after she has laid her egg so that her metabolism can be adjusted to take account of her action. This stimulus injects a small amount of pain and sleepiness and removes some progesterone to simulate the effects of birth. It also removes all comfort drive from the system, so that the female is free to go and wander as soon as she feels up to it! All of the learning boxes on the stimulus gene are ticked to prevent the brain from making associations with this action. The laying of an egg is an involuntary action, and so there is nothing that a creature can learn from egg laying they cannot decide to lay an egg!

Stimulus : Just mated
Expressed in both genders
This stimulus is passed to both male and female creatures just after a mating attempt, and makes adjustments to their biochemistry to take account of their activities! In an attempt to stop endless obsessive kiss-popping, the stimulus passes a small amount of libido lowerer into the system, as well as some tiredness to encourage resting. Sex drive and loneliness are reduced by mating hopefully it will be a couple of minutes before they are ready to try that again!

Stimulus : Tickled by opposite sex
Expressed in both genders
This stimulus is passed to a creature when one creature pushes another. This generally occurs when one creature is ready to mate but the other is not and so what would otherwise have been a kiss-pop is in fact a tickle. However, if creatures are at the point of tickling each other then there is some interest there, and so this gene injects a small amount of Arousal potential into the tickled party to encourage their biochemistry to catch up!

Stimulus : I'm home!
Expressed in both genders, but usually female related
This stimulus is passed to a creature when it reaches the home emitter in a terrarium. For Norns this emitter is located outside of the learning room, and this is where females head to lay their eggs when pregnant. The stimulus removes the drive that brings the creature to its home, and injects a little bit of boredom to encourage them to go and do something else once they get there.