Dolphins are aquatic mammals that belong to the infraorder “Cetacea” a group of animals that includes whales, dolphins, and porpoises. They also belong to the parvorder “Odontoceti,” which are the toothed cetaceans, but taxonomically speaking, dolphins are an informal group, composed by most toothed cetaceans but excluding whales and porpoises.
There are 43 different species of dolphins identified. 38 of them are oceanic dolphins which are those that most people know and five species of river dolphins. The families included as “dolphins” are the oceanic and river dolphins:
– Delphinidae (Oceanic dolphins)
– Platanistidae (Indus and Ganges river dolphins)
– Iniidae (Amazon river dolphins)
– Pontoporiidae (La Plata river dolphins)
– Lipotidae (Baiji or Chinese river dolphins)
Regardless the place they live, Dolphins have to reach the surface of the ocean to breathe at different time intervals. This cycle can last up to 30 minutes in some large species. The skin color of dolphins is grayish-blue, but it can also be black, white, light gray, blueish and even pink or the combination of those colors varying according to the species. However, in every case, their skin is very sensitive to impacts and other elements that could be in the water.
Even though some dolphin species have up to 100 teeth, they don’t use them for chewing. They use their teeth only to hold the fish and then swallow them. Large dolphins like the Orca can consume up to 500 pounds of fish per day. The pods usually work as a team to surround a school of fish and get them as packed as possible. Afterward, they plow through the middle of the fish concentration and eat as much as they need.
They even take turns doing this so the fish do not disperse and they all have the opportunity to get the food they require. This hunting technique is just one of the many different types of feeding strategies that they may use to reduce the effort of catching fish.
If we talk about charismatic animals, dolphins are probably on the podium. Enormously popular, significantly intelligent and scientifically sophisticated, they are amidst the most beloved animals among people. Dolphins have captured the human imagination in a variety of ways. They are curious, form strong bonds within their pod, and they have been known to help their peers and people in a variety of circumstances.
Warm-blooded means that their body is able to regulate its own temperature, so they stay warm even when the water temperatures around them are cold. Some of their native environments, such as the waters of the northern Pacific Ocean, can get very chilly. In these places, being warm-blooded is a big advantage for survival. Being warm-blooded also makes dolphins and other cetaceans less prone to infections and other health conditions that affect cold-blooded species.
Another central feature of marine mammals is that they have lungs, not gills. Dolphins, like whales, need to periodically come to the surface to replenish their air supply. They have blowholes that they close while diving, and then open at the surface for air.
Marine mammals have also adapted in some special ways to thrive in an aquatic environment. For instance, dolphins exchange 80% of the air in their lungs with each breath, while humans are only capable of exchanging 17%. Marine mammals also have a greater capacity for oxygen storage in their lungs, blood, and muscles. All of this creates a more efficient use of the oxygen in their bodies and is what allows many species to dive for extendedץ
Dolphins are considered one of the world's most intelligent animals, and they have several cognitive abilities that set them apart. Many researchers consider intelligence to be a combination of perception, communication, and problem-solving. You can see dolphin intelligence in action in the way they communicate and use tools.
Communication is a big part of how dolphins socialize and hunt. They have the ability to echolocate with a series of clicks, allowing them to find other dolphins or similar species and prey even in the low-light conditions of the ocean. They can do more, too. Did you know that dolphin echolocation allows them to detect surgically implanted metal in swimming humans? The human body is comprised of about 75% water, and once in the water, we provide a prime structure for echolocation. This is how dolphins are able to discern that the metal is denser than human flesh, which is mostly water.
Dolphins also have a complicated method of communicating with each other. From an outside perspective, dolphins may seem to communicate much like humans. However, researchers are still investigating both how dolphins communicate and what information they are able to pass to each other.
Despite lacking hands, dolphins are adept at using tools. For instance, one of their more specialized tricks is to carry a sponge at the end of their beak, also know as a rostrum. This acts like padding, protecting them from sharp rocks as they dig through the seafloor for food.
Dolphins are under threat worldwide, mainly human generated threats. Two of the biggest issues are entanglement in fishing gear and nets, and pollution. Dolphins often pursue the same fish species that commercial fishing ships are hunting and may get accidentally caught in their nets. They can also get tangled in discarded ropes and gear, causing a significant amount of marine mammal deaths each year. Finally, the human-created pollution that is affecting the world's oceans is causing a wide variety of problems for dolphins, ranging from diseases to difficulty finding food.
Dolphin habitats can be are found around the world, from tropical to temperate regions. Although they are warm-blooded, they tend to avoid oceans near the Arctic and Antarctic. The bottlenose dolphin, one of the most well-known species, prefers water between 50 and 90 degrees Fahrenheit. However, each species has its own preferences.
