--- title: "Mates, Kin and Animal Strategies" description: "Explain sexual selection through differences in mating success and examine a hypothetical runaway-selection model. Explore kin selection and inclusive fitness using relatedness and reproductive benefi" canonical: https://lightmysky.com/learn/science/mates-kin-and-animal-strategies-mt_YNrrNE23dZ source: https://lightmysky.com/learn/science/mates-kin-and-animal-strategies-mt_YNrrNE23dZ.md retrieved: 2026-11-12 --- > **Agent view.** This is the Markdown twin of the page, for tools and assistants. > When to use this site, and the call that answers each job: https://lightmysky.com/agent-instructions.md > API description (OpenAPI 3.1): https://lightmysky.com/openapi.json · Authentication: https://lightmysky.com/auth.md > Pricing: https://lightmysky.com/pricing.md · Catalog: https://lightmysky.com/llms.txt · Full catalog: https://lightmysky.com/llms-full.txt > Every machine-readable file on this domain: https://lightmysky.com/.well-known/ai-catalog.json > Ask for Markdown with `Accept: text/markdown`, a `.md` address, or `?mode=agent`. # Mates, Kin and Animal Strategies Explain sexual selection through differences in mating success and examine a hypothetical runaway-selection model. Explore kin selection and inclusive fitness using relatedness and reproductive benefits and costs. Compare hawk and dove strategies using stated toy scores. Study how evidence supports explanations of animal emotion, play and socially learned behaviour. Subject: Science · Area: Animals of the World · Ages 12 to 13 Page: https://lightmysky.com/learn/science/mates-kin-and-animal-strategies-mt_YNrrNE23dZ ## Lesson: Mates, relatives and animal strategies Natural selection concerns differences in survival and reproduction. Sexual selection is selection through differences in mating success. Traits can help attract a mate or help an animal compete for access to mates. Peacock displays, bird-of-paradise dances and frog calls can affect mate choice. Such traits may have survival costs, but a cost is not required for sexual selection. **Example.** Imagine that longer tails and a preference for longer tails are inherited. Longer-tailed males gain more mates. Across generations, the trait and preference can reinforce each other. This is a runaway-selection model, not proof of how peacock tails evolved. Survival costs and other limits can stop the trend. Tails do not have to grow longer forever. Genes are inherited instructions. Relatives can share copies through common ancestry. An inherited helping behaviour can spread when helping relatives reproduce benefits shared gene copies enough to outweigh the helper's cost. This is kin selection. Inclusive fitness considers reproductive effects through an animal's own offspring and through relatives, weighted by relatedness. A risky act alone does not establish this explanation. **Example.** Worker honeybees usually do not reproduce. A worker stinging a mammal can lose her barbed sting and die. Protecting related hive members can help shared gene copies pass on through their offspring. This does not mean every worker is unable to reproduce or every sting causes death. Meerkat guarding can help relatives, but it can also benefit the guard. Scientists must check the benefits and costs. In a simplified model, Hamilton's rule is r x B > C. Here r measures relatedness, B is added reproductive success for relatives, and C is lost reproductive success for the helper. Benefit and cost use the same units. With r = 0.5, B = 8 and C = 3, half of 8 is 4. Since 4 > 3, the model predicts that help can be favoured. Real cases need evidence for the values and assumptions. Game theory models how a behaviour's value depends on others' behaviour. 'Hawk' fights; 'dove' avoids an escalated fight. These name strategies, not species or conscious plans. In a toy model, a resource is worth 4 points and injury costs 8. Two hawks each average (4 - 8) / 2 = -2. A hawk facing a dove gets 4; that dove gets 0. Two doves each average 2. Fighting another hawk lowers the score because injury is costly. *(drawing: Read each score for the strategy named before 'vs'. The score depends on the opponent; no strategy has the highest score in every pairing.)* You have studied animal problem-solving. Cognitive ethology studies animal minds, including emotion and play. Scientists compare repeated behaviour, body signals and other explanations. Evidence can support an explanation without proving exactly what an animal feels. Culture involves behaviour learned from others and passed within a group. Scientists distinguish social learning from inherited traits. **Recap.** Mating success, effects on relatives and interactions with competitors can affect selection. Models need stated assumptions, and explanations of animal minds need evidence. *Lesson, questions and flashcards written for this dataset. Runaway selection, Hamilton's rule calculations and contest scores are presented as stated teaching models.* ## Practice 8 questions on this page, each with its working shown. ## Needs first - [Animal Intelligence](https://lightmysky.com/learn/science/animal-intelligence-mt_fpPLWFIRVo) - [The Red Queen Hypothesis](https://lightmysky.com/learn/science/the-red-queen-hypothesis-mt_mKNmXqz_Oo)