|09-21-2003, 08:24 PM||#1 (permalink)|
Deaf sea lion gets a home
Thursday, August 7, 2003
Visitors to Brookfield Zoo's Pinniped Point exhibit probably would not notice anything unusual about Harley, a 2-year-old sea lion, from just watching him swim in his pool.
But upon closer observation, visitors may notice zookeepers using hand signals rather than auditory cues to communicate with Harley during daily training sessions. That's because the California native is deaf.
It is not known how Harley lost his hearing. He was discovered stranded on a beach and sent to the Marine Mammal Center. Veterinarians examined him thoroughly and discovered he could not hear, no matter how loud the noise.
CT scans, similar to those used on humans, were done by staff from the University of California-Davis and read by a marine mammal hearing specialist. The scans showed an abnormal formation of Harley's hearing bones, thus indicating that the deafness may be something he inherited, was born with, or incurred from some trauma earlier in his life.
When the center determined the hearing impairment would prevent a release back to the wild, Harley was given a home at Brookfield Zoo. Sea lions need to hear to survive in the ocean. They need to hear other sea lions' vocalizations to claim territory. And, they need to hear the clicks and sounds made by their chief predators, killer whales.
The training sessions at Brookfield Zoo allow Harley's trainers to provide him with the best possible care. Using positive reinforcement, keepers are training Harley to follow them, touch a target, hold his position, roll over and even participate in his own health care by opening his mouth and presenting a flipper to have blood drawn.
Harley can be seen, along with his pool pal, J.R., a 17-year-old sea lion, at Brookfield Zoo's Pinniped Point. In spring 2004, the two will be joined by the zoo's three female sea lions, currently on loan at a facility in California.
California sea lions are marine mammals that live along the Pacific coast of North America, from Vancouver, Canada, to Baja, Mexico. They gather in large groups on rocky beaches and hunt for fish in the waters offshore.
In the early part of the 20th century, sea lions were hunted, both for their skin and to reduce competition with fishermen for fish. As a result, their populations declined.
Today, sea lions, like all marine mammals, are protected by the Marine Mammal Protection Act that was established in 1972. There are now thousands of sea lions along the Pacific coast. In some coastal cities, such as San Francisco, they hang out by the hundreds on rocks in the bay.
Brookfield Zoo is off First Avenue, between the Stevenson (I-55) and Eisenhower (I-290) expressways. Phone: (708) 485-0263, Ext. 216.
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