Photo by Vincent LeColley
Courtesy of USA Today, we’re continuing our list of surprising similarities between humans and dolphins. Did you know:
4. Some live in small groups.
The size of the pod varies, but most groups are between two and 30 members. In areas where there is plenty of food, super pods of dolphins can be as big as 1,000 members, which can also help to fend off predators.
5. Adults raise the young.
Gestation in dolphins is between 10 to 17 months, depending on the species. After the calf is born, the mother nurses it for up to two years and the calf remains with the mother until it reaches puberty, between 5 and 10 years old. The mother’s bond with a male calf is usually very strong and continues until the calf is 6 or 8 years old. The mother and the calves join groups for protection. The male dolphins play no role in this group. They form alliances with other male dolphins that can last for as many 20 years.
6. They engage in cooperative hunting.
Dolphins are cooperative hunters and those skills are passed along to younger members of the pod. In a paper written by the Royal Society in 2005, researchers in Florida observed feeding behavior in two groups of bottlenose dolphins and saw one individual, or “driver,” herd fish toward the rest of the pod of dolphins.
7. We have sleep genes.
Yes, dolphins sleep, but not the way we do. For land mammals, sleep means partial or complete unconsciousness, muscle inactivity, and a shutdown of the senses. For dolphins, their sleep is called “unihemispheric slow-wave sleep.” That means a dolphin will shut down one side of its brain and close its opposite eye. The other side of the brain keeps a lookout over its environment — which is much more hostile than ours — and controls breathing.