A ‣ Describing animals and birds 
mammal: animal that gives birth to live babies, not eggs, and feeds them on its own milk (e.g. cat, cow, kangaroo); a kangaroo is a special kind of mammal called a marsupial [its young grow in a pouch in front of the mother]
rodent: e.g. mouse, rat
reptile: e.g. snake, lizard
carnivore: animal that eats a diet that is mainly or exclusively meat (e.g. lion, tiger, hyena)
herbivore: animal that eats a diet that is mainly or exclusively grass/vegetation (e.g. deer, cow)
predator: animal that hunts/eats other animals (e.g. eagle, lion, shark)
scavenger: animal that feeds on dead animals which it has not killed itself
warm/cold-blooded: warm-blooded animals (e.g. mammals) have temperatures that stay the same; cold-blooded animals (e.g. reptiles) have to control their temperature by taking in heat from outside or by being very active
B ‣ Describing typical animal behaviour 
Our old cat is a very docile creature. [behaves very gently]
These birds are so tame, they will sit on your hand. [not afraid of humans, usually because of training or long involvement with humans]
Dogs and horses became domesticated thousands of years ago. [live with or are used by humans]
There are wild cats in the mountains. [opposite of domesticated]
A savage wolf killed three of the farmer’s sheep. [extremely violent or wild]
A fierce dog guarded the gates. [behaves aggressively]
C ‣ Life of animals and birds 
As more buildings and roads are constructed, the natural habitat for many species is shrinking. [preferred natural place for living and breeding]
The arctic tern is a bird which migrates from the Arctic to the Antarctic, a round trip of over 70,000 km. Migration is when animals travel long distances to get to a different habitat.
The dodo was a large flightless bird which was found on one island in the Indian Ocean but became extinct in the 17th century. [died out]
You can see lots of animals in the big game reserves / game parks in Africa. [areas of land where animals are protected from hunting, etc.; game can be used to mean animals or birds that are hunted]
There is a bird sanctuary near here. [protected natural area where birds can live and breed]
We went to the local animal (rescue) shelter to see if we could get a dog there. [place where stray cats, dogs, etc., i.e. pets that have lost their home, are given food and a place to live]
Language help
A dodo is now used to mean someone or something out of touch or obsolete.
D ‣ Human exploitation of animals and birds 
Many people are opposed to blood sports such as foxhunting and bullfighting. [sports whose purpose is to kill or injure animals]
Some people refuse to wear clothing made of natural animal fur, since they are opposed to the fur trade. [the selling of animal furs for coats, jackets, etc.]
Poachers kill hundreds of elephants every year to supply the ivory trade. [people who hunt animals illegally] [the buying and selling of ivory from elephants’ tusks]
Animal rights activists often demonstrate outside research laboratories where animals are used in experiments. [people who actively campaign for the protection and rights of animals]
Rhinos are hunted for their horn, which is said to have healing powers. [hard, pointed, often curved part growing from the head of an animal]