RODENTS
With over 2,000 species, rodents make up the largest group of
mammals. The smallest rodents weigh just a few grams. The largest,
South America’s capybara, is the size of a large dog. All rodents
have chisel-like incisor teeth at the front of their jaws to gnaw food.
PRIMATES
These mostly tree-living mammals are divided into two groups.
Prosimians, or primitive primates, include lemurs, lorises, and
tarsiers. Anthropoids, or higher primates, include marmosets, apes,
monkeys, and humans. Primates range in size from mouse lemurs
weighing 100 g (3½ oz) to gorillas, which are 2,000 times heavier.WHAT FEATURES DO ALL PRIMATES SHARE?
Primates are intelligent mammals. As well as hairy
bodies, most have long arms and opposable thumbs
and big toes, which enable them to grasp branches.
Primates’ eyes face forwards, giving them binocular
vision, which helps them judge distances as they
swing through the trees. Their main senses are sight
and touch; hearing and scent are less important.1 PREHENSILE TAIL
Many South American monkeys,
such as this red howler, have a
grasping tail. African and Asian
monkeys’ tails are not prehensile.WHY DO MANY PRIMATES LIVE IN GROUPS?
By living in groups, primates can defend large feeding
territories and are more likely to spot predators than
they would on their own. Group living also helps with
raising young. Primate babies take a long time to grow
up – three to five years in apes such as chimpanzees.
Having other adults around helps take the burden off
mothers and gives the babies added protection.WHERE ARE RODENTS FOUND?
Rodents can survive almost anywhere except the sea.
Marmots and lemmings inhabit snowy mountains and
Arctic wastes, while jerboas and gerbils live in deserts.
Rats and mice have colonized our towns and cities.
Different rodents are adapted for climbing, swimming,
burrowing, or gliding through the air.
WHAT DO RODENTS EAT?
Most rodents are plant-eaters,
searching out food with their
sensitive noses and long whiskers.
Razor-sharp incisor teeth make
short work of nuts and seeds. Some
rodents carry food in cheek pouches.1 BABY HOUSE MICE
Rodents breed very quickly.
Mice can produce up to 50
offspring in a year, which grow
up so fast that they themselves
are ready to breed in six weeks.
Rodent populations multiply
quickly when food is plentiful.4 BUSY BEAVER
Beavers fell trees with their
teeth to dam rivers and form
lakes. They build a home called
a lodge in the middle of the
lakes, where they can rear their
young in safety. The lodge’s
entrance is under water.4 CHIMP CRACKING NUTS
Apes are the largest and most intelligent primates. Some apes use tools.
Chimpanzees, for example, use stones as weapons or to crack nuts, moss
to soak up water, and sticks to probe for insect food.