When discussing the book with your students, refer to this list of sibling characteristics. It highlights the differences and similarities between the featured animals.
- They have one baby at a time.
- The older sister looks after the baby.
- Males leave the herd, but females stay to take care of the other elephants
Gould’s long-eared bats
- Mother bats usually have twins.
- The babies leave their mother around four months of age.
- They are always born as identical quadruplets, four brothers or four sisters.
- They are perfect copies of each other.
New Mexico whiptail lizards
- They have only sisters; there are no male whiptail lizards.
- The lizards are always identical to one another.
- They produce babies without needing a male (plants often reproduce this way, but it is rare for animals).
- Their identical nature can be fatal. If one gets a disease or has a change in habitat, all the lizards can be affected.
Naked mole rats
- One queen mole rat produces hundreds of offspring.
- They have a social system that means one rat can have a higher or lower status than a sibling.
- Millions of brothers and sisters live in a single nest called a mound.
- One female can produce 30,000 eggs a day.
- Every sibling has a job. Some worker termites do things like repair the nest, look for food, and take care of the queen. Some males defend the nest.
- Grizzly bears are usually born two to three to a litter.
- Young males play, but as they get older, their play can turn to fights.
- So they don’t get seriously hurt, older brothers usually leave and go off on their own to find new territory.
- Pups are usually born two at a time.
- If pups consist of one brother and one sister, they will get along okay. If both are the same sex, they usually start fighting while very young, and the weaker one may die because their fighting can get fierce.
- Full-grown hyenas are among the fiercest animals on earth, and their sibling fights are serious fights.
Black widow spiders
- 700 baby spiders can be born in one egg sac about the size of a grape.
- Only few survive, however, because black widows are cannibals. As soon as they hatch, the stronger spiders begin to eat their brothers and sisters.
- Male black widows are not dangerous to people, but females are the most venomous spider in North America.
- Females often eat the male after mating.
- Cheetah cubs play hunting games to learn how to hunt.
- At about two years old, sisters leave their siblings to start their own families, but the males stay together and hunt together throughout their lives.
- These birds practice hunting with their siblings. They take turns being the hunter or the prey.
- They hunt by swooping down and striking a duck or pigeon at speeds up to 200 miles per hour. This stuns or kills the prey. They are careful not to injure each other, however, when practicing with their siblings.
- Wild turkey brothers are friends for life.
- A wild turkey mother lays 10 to 12 eggs in the spring. They stay with their mother and siblings for a year.
- The females leave to start their own family. The males stay together for the rest of their lives.
- There are three to five baby beavers, or kits, in a litter.
- Siblings help their parents build dams, repair their dens, and collect food. They stay with their parents for about two years.
- A mother croc buries 40 to 50 eggs in a large pile of mud and leaves.
- A baby can’t leave the nest on its own, so it calls its mother from inside the egg.
- The babies all call the mother at once, making a chorus of cheeps. When the mom hears the cries, she picks the eggs up in her mouth and rolls them gently to help the babies get out of their shells.
- Once out of their shells, the babies work together again to make a loud cry that warns the other sisters and brothers of any danger. Then they all run to their mother and crawl into her mouth where they stay until danger passes.
- These are among the smallest animals on earth. A litter of 10 can fit in a teaspoon.
- Shrews hunt day and night.
- Because they are so small, they can get separated from their siblings.
- To avoid this, they caravan. With the mom in lead, a baby grasps the mom’s fur with its teeth, just above her tail. The next baby grasps its brother or sister in the same way, and then the next, and the next, until they’re all attached in a line.
Great crested grebe
- After birth, baby grebes ride on their mother’s back, hiding under her feathers.
- When the babies are too large to carry, the mother shakes them off, and they learn to swim on their own.
- Siblings stay close together with their mother. When about 10 weeks old, the chicks leave the family group.
- After she lays her eggs, the mother carries the eggs in her mouth to keep them safe.
- Sometimes a nearby cuckoo catfish will eat some of the new eggs and put her own down in their place. That means the mother cichlid picks up the catfish eggs along with her own. She raises them as if they were her own babies.
- Asian koels sometimes lay an egg in the nest of other birds, like a myna bird.
- The myna takes care of the Asian koel along with her own baby birds, even though the orphan bird is twice as big as the myna babies.
- Sometimes the bigger bird pushes the mynas out of the nest, but often they are all raised together.
- When old enough to fly, the koel leaves the myna family.
- Anteaters have one baby at a time. It rides most of the time on its mother’s back for the first year.
- Because it goes off on its own before its mother has another baby, anteaters never know their siblings.
This teacher sheet is a part of the Sisters & Brothers: Sibling Relationships in the Animal World