Mammals Landing

You have chosen a career to follow and prepare for, now it’s time to learn more about the species (and breeds) you will work with. 

Read about the basic facts and join one of the Mammals Groups to learn even more about the specific species, as well as how to work with them, and how to gain experience if you want to work with them. If you are not a member, join us in the OZT Community!

Definition of Mammal

A warm-blooded vertebrate animal of a class that is distinguished by the possession of hair or fur, females that secrete milk for the nourishment of the young, and (typically) the birth of live young.

Basic Facts

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Assumed to originate from a line that diverged away from the reptiles about 300 million years ago.

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Different species of mammals have evolved to live in nearly all terrestrial and aquatic habitats on Earth. Mammals inhabit every terrestrial biome, from deserts to tropical rainforests to polar icecaps. Many species are arboreal, spending most or all of their time in the forest canopy.

Global Population

Global Population

It is estimated that the total number of wild mammals in the world is about 130 billion. The mammal with the highest population is cows, estimated at around 1.5 billion.

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The smallest mammal is the Kitti's hog-nosed bat with a length of about 1.1 to 1.3 inches (29 to 33 mm) and weighing less than 0.07 oz (2 g). The largest mammal is the Blue Whale at 98 feet (30 m) in length and 200 short tons (180 metric tons) or more in weight.



Lifespan ranges from a year or two in some rodents, to over 150 years for certain species of whale.



Most mammals are viviparous, giving birth to live young. However, the species of monotreme (the platypuses, marsupial moles, the echidnas and a few others) lay eggs.

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Between 12 to 13 days for the Opossum, to about 640 to 660 days (or roughly 95 weeks) for Elephants.

Main Diet Icon

Main Diet

The diets of mammals span across all three main dietary groups: herbivores, carnivores and omnivores.

Do you have information that you would like to contribute to this course? Please click on the red beetle to access the contribution form.

OZT Community Logo

Join one of the Groups

Status: All Active

Amount of Mammal Groups: 4

Learn even more about mammals and specific groups of species by joining either the general, or one of the three specialized Groups.

Members of the 4 Groups can access all the different Short Courses, specific to the kind of species in the Group, as well as win awards and meet other mammal lovers from around the world. Gain points with each short course and compete for the top spot on the leader board!

Four Groups:

  • ^ General Mammal Group (all mammals)
  • ^ Primates
  • ^ Marine Mammals
  • ^ Wild Cats

Topics covered in each of the MAMMAL GROUPS:

  • ^ Anatomy
  • ^ Habitat
  • ^ Behaviour & Diet
  • ^ Ecological Benefits & Conservation
  • ^ Species (courses on over 300 different species)


This is also the place where you will find links to all of the Animal Organizations that work with mammals. Join their special Groups and learn how you can gain valuable experience by volunteering or interning with them.

Career Profiles and Resources

Contributions by expert members are always appreciated to allow the students to make informed decisions. Please add your contribution through the attached form:

Contribution Form

List of Species Mentors/Educators who have contributed to the info:


One Zoo Tree

A few excellent pictures as examples of the species