World's largest elephant was heavier than two school buses

"How much does an elephant weigh?," asked Ryan Gertz, 8, a second-grader at Robert Crown Elementary School in Wauconda.

Elephants, also known as pachyderms, as super-sized. The very largest elephant weighed 24,000 pounds -- that's more than the weight of two school buses. "Just like people are different, animals are different. There can be a lot of variation in weight," said Rick Lichtner, lead keeper at Brookfield Zoo's Pachyderm House.

In their native territory these gigantic creatures bulk up on grass, shrubs, trees, twigs and bark, eating 5 percent of their body weight every day.

Elephants' super-sized appetites have placed them in the dog house -- farmers in Africa complain that a herd can wipe out their crops. Experts are trying to develop strategies that will protect the endangered species and help farmers at the same time.

There are two elephant species, African and Asian, and it's easy to tell them apart. African elephants are much larger than Asian. Males can weigh about 12,000 pounds. Their ears are extremely large and shaped like the African continent. All African elephants have tusks and a curved back. Asian elephants are smaller in size and have smaller ears and a dome-shaped back. They range in weight from 6,500 pounds to 11,000 pounds. Only the males have tusks.

Elephants start out big. A baby elephant, called a calf, stands about 3 feet tall at birth. Average baby weight is 220 pounds.

Elephants are social animals and live in small groups called herds. They are led by a matriarch -- a female leader -- usually the oldest in the group. When the males, called bulls, become teenagers, they leave the herd and return only to breed.

Brookfield Zoo is home to two African elephants -- Affie, 38, and Christy, 27. Affie is unusually large for a female at 9 feet tall and more than 7,000 pounds.

How do you keep a 7,000-pound animal in shape? Lichtner said they place pedometers on the elephants to measure their activity levels. Results show that Affie and Christy walk at least two miles a day. "They have exercise sessions every day," Lichtner said. Workouts include walking and a stair-master-like exercise that involves lifting their giant feet onto different sized tubs.

Ever see an elephant dressed in a sweater? You'd think our cold winter temperatures would send them packing their trunks. But even their desert homes can get cold when the sun goes down.

"They are acclimatized," Lichtner said. "In Africa at night it can get down into the upper 30s." In the summertime, the zoo keepers offer the elephants a few ways to beat the heat. They have a pool, a mister and shade. When it's really hot, they head inside.

Want to learn more about animals? Check out the Brookfield Zoo's "Field Guide To Animals" on the zoo Web site www.brookfieldzoo.org. You can learn many facts about the zoo's resident animals -- where they live, what they look like, if they are endangered, where their natural habitats are located and if they are part of the multi-zoo specials survival plan that assists in increasing species populations.