Lights Out for Hatchlings
1Each summer, the conservation team at Bayside Zoo works with wildlife biologists to protect sea turtle nests on a nearby beach. Sea turtle hatchlings usually leave the nest at night. On a natural beach, the open sky over the ocean is often a little brighter than the dark dunes and trees behind the beach. Light-sensitive cells in a hatchling's eyes detect the difference, nerves carry signals to its brain, and the brain sends signals that move its flippers. Most hatchlings crawl toward the brighter, lower horizon.
2Biologists on the team noticed tracks heading inland near houses with porch lights. To test lighting, they used a round arena with a sand floor in a dark room. A dim, glowing panel on one side copied the night sky over the ocean. On the opposite, land side they could place a lamp. Both lamps were cool LEDs set to the same power, so neither one warmed the sand. Each hatchling was placed in the center once, its direction was recorded, and it was released on the beach that same night. Every setup used 20 hatchlings that had never been tested before.
3Zoo keepers also use senses to train animals for health checks. A young river otter named Pip was learning to swim to a flat rock station when a keeper blew a whistle. Each time Pip reached the station within 5 seconds, the keeper gave a small piece of fish. Every training day, at the same time before lunch, the keeper blew the same whistle at the same loudness 10 times. Pip ate the same amount of food each day.