Dolphins are fascinating animals and universally loved by pretty much everyone. They are cute, playful, and always draw a crowd when they decide to surface. Ready To Learn Dolphin Facts? Let’s Begin!
1. Dolphins Are Carnivores
Dolphins eat a wide variety of foods, including fish, squid, octopus, crustaceans, cephalopods, and other marine life. Smaller dolphins usually stick to a diet of fish and other small prey. Larger dolphins, such as the killer whale (bet you didn’t know that a killer whale is actually a dolphin!) eat larger things, like sea lions, seabirds, sharks, and penguins. To capture their food, dolphins often work together to surround and circle their prey in order to keep it from escaping. They keep circling until they have the prey forced into a small and dense ball. Once it’s trapped, the dolphins take turns swimming through the circle to pick off the fish who can’t escape. Some other dolphins will work to force their prey into a corner or into a shallow riverbank or shallow water along the coastline. This makes it difficult for their prey to escape. Dolphins do have teeth, but most of them don’t use them to chew their food and swallow it whole, head first, so the scales on the food do not disturb their throat. They use their teeth to defend themselves and to grip objects. They actually have two stomachs: one for food storage and one for digestion.
2. Dolphins Only Sleep with Half of Their Brain
Dolphins and whales sleep in an unusual way. Called “unihemispheric slow-wave sleep,” it basically means that they sleep with only half of their brain. When a dolphin goes to sleep, it shuts down one hemisphere of its brain and closes the opposite eye. This allows the dolphin to monitor what’s going on around them and to regulate breathing. While they are sleeping, some dolphins are motionless at the surface of the water. Other times, they might swim slowly. Over a 24-hour period, each side of a dolphin’s brain gets about 4 hours of sleep. Dolphins evolved into this sleeping style for a few reasons. They need half of their brain to control their breathing and to watch out for danger while they rest. If they aren’t aware of their surroundings, they could be prey for bigger ocean predators. Sleeping with half of their brain also allows certain physiological processes, like muscle movement, to continue. These processes help warm-blooded mammals, like dolphins, maintain the body heat they need to survive in the ocean.
3. Dolphins Live a Long Time
The life expectancy of dolphins vary, but the common bottlenose dolphin can live a whopping 20 to 50 years! To determine a dolphin’s age, veterinarians can count the rings inside each tooth. Each growth ring indicates one year of life. Things that impact how long a dolphin lives include their habitat, diet, health status, species, geography, and their level of endangerment. Dolphins in captivity generally have a shorter lifespan. Even though they are protected and well cared for, they still live a shorter time in captivity. Things like their diet, lack of a strong social structure, and a closed environment contribute to this shorter lifespan. The most critical time for mortality is during the first two years of a dolphin’s life. This is when they are most susceptible to disease, predators, and adverse climate conditions.
4. Some Whales are Actually Dolphins
Orcas, which are very recognizable because of their black and white coloring, aren’t actually whales. In fact, they are part of the dolphin family. Sometimes called killer whales, they are the biggest members of the dolphin family and found in every ocean in the world. Like dolphins, they are very intelligent and able to communicate. They coordinate with other whales in their pod to hunt their prey. If killer whales are actually dolphins, why do we call them that? The name killer whale came from ancient sailors who observed orcas hunting and preying on other whale species. They called them “asesina ballenas” which translates to whale killer. Eventually, the names were flip-flopped, and the term killer whale was born.
5. A Dolphin Can Swim More than 20MPH
They didn’t call Flipper “faster than lightning” for nothing! Dolphins have been clocked at speed up to 25 miles per hour when they’re in a hurry or trying to get away from something. Their normal swim speed is about 7-8 miles per hour though. To swim this quickly, dolphins use their tail, or fluke, to produce thrust to push them through the water. The flukes act as wings to generate a lift force that pushes them forward. The flukes are flexible and dolphins can control that flexibility. As they swim faster, the fluke might become stiffer. Researchers are still trying to pinpoint how exactly they control the flexibility of their flukes.
