Animal behaviour is anything an organism does in response to stimuli from its environment or other organisms. Behaviours can be innate — genetically programmed and present from birth — or learned through experience. Natural selection favours behaviours that improve survival and reproduction, so behaviour evolves just as body structures do.
What is innate behaviour?
Innate behaviour is a response that is inherited and does not require learning. It is present from birth (or hatching), is performed in the same way by all members of the same species, and does not improve with practice. Innate behaviours are often called instincts.
Examples of innate behaviour include:
- A newborn baby turning towards a nipple and sucking (the rooting reflex)
- A spider constructing a web correctly the first time it builds one
- A herring gull chick pecking at the red spot on its parent's beak to stimulate regurgitation of food
- A mayfly emerging, mating, and dying — all within 24 hours, with no possibility of learning
Innate behaviours are controlled by fixed neural pathways, encoded in the genome. They tend to be fast, reliable, and appropriate for situations the animal is very likely to encounter — but they cannot adapt to novel situations.
What is learned behaviour?
Learned behaviour results from experience and changes over an individual's lifetime. It allows an animal to adapt to new environments or improve performance beyond the baseline set by instinct. Learned behaviour is not heritable directly, but the capacity to learn is itself genetically determined and subject to natural selection.
Key forms of learned behaviour include habituation, imprinting, classical conditioning, and trial and error (operant conditioning):
- Habituation: an animal stops responding to a repeated stimulus that has no reward or threat. A rabbit that initially flees every time it hears a car will eventually ignore traffic noise if the noise has never been followed by danger.
- Imprinting: very young animals learn to follow and recognise the first moving object they see after hatching or birth. Newly hatched greylag goslings famously imprinted on the ethologist Konrad Lorenz rather than their mother, following him instead.
- Trial and error: an animal tries different behaviours and repeats those that produce a reward. A rat in a maze learns the route to food by gradually eliminating wrong turns.
What are courtship displays and why do they occur?
Courtship is behaviour that allows animals to identify a mate of the correct species, assess their quality as a potential partner, and synchronise their reproductive cycles so that fertilisation can occur at the right moment. Courtship displays can be visual (peacock's tail), acoustic (birdsong), chemical (pheromones in moths and mammals), or tactile (mutual grooming in chimpanzees).
Why displays are elaborate: natural selection has shaped courtship over generations because:
- Mating with the wrong species wastes reproductive effort.
- A more complex or energetically costly display signals that the individual is healthy and genetically "fit".
- Synchronisation ensures eggs and sperm are ready at the same time.
The peacock's tail is the classic example of sexual selection: the huge tail is costly to grow and makes the male conspicuous to predators, yet it has evolved because females consistently prefer males with larger, more symmetrical tails, giving those males more offspring, who in turn carry genes for large tails.
What is communication in animals?
Communication in animals is the transfer of information between individuals that influences the behaviour of the recipient. It serves survival and reproduction:
| Signal type | Example | Purpose |
|---|---|---|
| Visual | Bee waggle dance | Direction and distance of food source |
| Acoustic | Wolf howl | Territory marking; pack location |
| Chemical (pheromone) | Female moth release | Attracting mates over kilometres |
| Tactile | Primate grooming | Social bonding; parasite removal |
| Electrical | Electric eel pulse | Navigation; communication in murky water |
Bees use a particularly complex chemical and dance-based communication system to convey the precise location of food sources: the waggle dance indicates direction relative to the sun and distance by the duration of the waggle run.
How does natural selection shape behaviour?
Every behaviour has a genetic basis in the neural wiring and hormone systems that produce it, and that genetic basis is inherited. Behaviours that increase survival and reproductive success become more common across generations; those that reduce fitness become rarer. This is identical to the mechanism that shapes physical traits.
Examples:
- Birds that learn to avoid brightly coloured prey (warning colouration) survive longer and reproduce more — learning capacity is selected for.
- Migration routes in some bird species are partly innate (a direction and distance encoded in the genome); birds that fly a slightly wrong course fail to reach wintering grounds and die — the correct route genes become more common.
- Cooperative behaviour (e.g. meerkats standing guard, calling warnings) is maintained by kin selection: the guard helps relatives who share its genes, so the "guarding" gene is spread even if the individual guard is occasionally taken by a predator.
Frequently asked questions
What is the difference between innate and learned behaviour?
Innate behaviour is genetically programmed and present from birth — it does not require any experience and is the same in all individuals of the species. Learned behaviour develops through experience and can vary between individuals. In reality most animal behaviour is a blend of both: a bird has an innate predisposition to sing, but the precise song dialect is learned from neighbouring birds. Natural selection acts on both — the capacity to learn, and what is learned, both have fitness consequences.
What is habituation and why is it useful?
Habituation is a decrease in response to a stimulus that has been repeated many times without consequence. It is the simplest form of learning: the animal essentially learns to ignore meaningless signals. It is useful because responding to every stimulus is energetically costly and distracting — a rabbit that freezes every time a leaf falls would spend so much energy on unnecessary responses that it would miss real predator cues. Habituation allows animals to filter out background noise and focus on genuinely important signals.
How does courtship benefit both males and females?
Courtship benefits both partners by ensuring they mate with the correct species (reducing wasted reproductive effort), by allowing assessment of mate quality, and by synchronising reproductive cycles. Females typically benefit most from being choosy, because eggs are more costly to produce than sperm and females bear a higher burden of parental care in most species. Males benefit from displays that honestly signal their genetic quality, because a female who chooses them will produce fitter offspring.
Why do some animals live in groups rather than alone?
Group living offers benefits that outweigh the costs in environments where those benefits are large. Benefits include collective vigilance (more individuals watch for predators), cooperative hunting (wolves, orca), cooperative breeding (meerkats, naked mole rats), shared knowledge (older elephants know water sources), and warmth (penguins huddling in Antarctic winters). Costs include competition for food, mates, and shelter, and increased disease transmission. The balance shifts in different environments, which explains why group size varies enormously between species.
For Socratic KS3 biology with Professor Darwin — asking first whether a behaviour would have increased fitness in an ancestral population before deciding whether to call it innate, learned, or both — visit aitutors.me.