Wildlife Encounters - 9th - 12th grade
Lesson 2: Wildlife Populations
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Adaptations: Fecundity

Fecundity is the ability to produce offspring. It can also describe the reproductive rate of an individual organism. Fecundity can be influenced by the availability of resources and the presence of potential mates.

Having high fecundity is an adaptation of many wildlife species. It is unusual for humans to have more than one baby at a time. However many wild animals have multiple babies at once. In fact, all animals produce more offspring than can survive long enough to reproduce themselves. This increases the likelihood that at least one offspring will survive to adulthood to carry on the genetics of the parent.

The number of offspring produced is often related to the amount of parental care. Typically, the higher fecundity, the lower the amount of time parents devote to caring for the offspring. Animals have limited amounts of energy they can use for reproduction. Animals with high fecundity spend their energy in the production of many offspring that do not require much care. Alternatively, animals with low fecundity produce fewer offspring, and have more energy to care for those offspring.

The scale below shows the spectrum the fecundity of various wild animals.

fecundity chart

Fecundity Quiz

Read the questions below, then click on the question to see the answer. Click again to close the answer box.

What do animals with low fecundity have in common? What do animals with high fecundity have in common? Hint: think about the natural history of these animals.

Answer: Animals with high fecundity are often prey animals, whereas animals with low fecundity are less likely to be food for predators. Prey species like mice and rabbits have higher losses of offspring to predation. For these species, having high fecundity increases the likelihood that some of the offspring will survive to reproduce themselves. Animals like elephants and owls have fewer natural enemies, and can afford focus more energy on fewer offspring since their babies are more likely to survive to adulthood.

Recall the natural histories of the red fox, fox snake, fox squirrel, and fox sparrow. Which would you expect to have high fecundity? Which would you expect to have low fecundity?
Answer:  Fox snakes have the highest fecundity of these four species, and can lay up to 84 eggs at once!  Like many reptiles, after laying their eggs in a nest, they abandon the eggs.  They spend their energy of the production of offspring rather than the care of offspring.  As with other rodents, fox squirrels also have high fecundity.  They can produce up to 10 offspring per year, and by four months of age, squirrels are completely independent.   Although they can produce up to 13 babies or kits in one litter, red foxes typically have 4-6 kits.  Fox sparrows lay 3-5 eggs each year.  Both red fox and fox sparrows must spend a large amount of time caring for their offspring early on, so it is less practical to have higher fecundity for these species
Adaptations: Predator vs. Prey