The following questions were answered by zoo nutritionist Ellen Dierenfeld of the Bronx Zoo and zoo biologist Will Waddell of the Point Defiance Zoo.

What is the largest zoo animal?
The largest zoo animals are the elephants. Some of the males can weigh between 10,000–12,000 pounds!

What is the largest animal alive today?
Blue whales are the largest living animals. They can reach up to 90 feet long and weigh 150 tons!

Do all animals have red blood?
All animals (not counting insects) do have red blood. There is a lot of variety in size, shape, and number of red blood cells between animals. Also, the red blood cells in mammals are different than in birds and reptiles — mammals'blood cells are "non-nucleated," whereas those other critters have nucleated red blood cells. The "blood" in insects is called hemolymph. All you need to do is check the wind-shield of your car in the summer to see what it looks like.

Why do animals have hair?
Mammals are the only animals that have hair, although some have more than others. Hair basically protects the skin from the sun, against the cold, and in some cases from predators (like porcupines).

Which animal can live the longest in captivity?
Probably the reptiles (crocodiles, alligators, turtles) can live the longest in zoos, provided all conditions (like temperature, food, and housing) are appropriate. We had a marabou stork that held our longevity record of 80 years, though. Large mammals (elephants, gorillas) typically live 30–50 years or more. Most animals actually have longer lives in zoos than in nature — think about how many fewer stresses exist in their daily lives!

Do you separate babies from their mothers in the zoo?
We don't separate babies from moms in our facilities as a rule, as often hand-rearing results in strange behaviors and other problems. If a parent rejects an infant or cannot properly care for it, we will attempt to hand-rear or supplementally feed the baby, but it's always better to leave kids with their moms.