Although dolphins have blubber instead of fur that help hold in its heat and give it a streamline shape, it is true that dolphins do have hair, but only a tiny bit. The only place that they have hair is right next to their blowhole. Though most dolphins do not have hair, they do have hair follicles. These hair follicles are believed to perform some sort of sensory function. For instance, the small hairs found on the Boto river dolphin are believed to function as a tactile sense possibly to compensate for the creature’s poor eyesight.
The sex life and reproduction of a dolphin is quite fascinating and differs from many other mammals in a few ways. Dolphins have been found to most often reproduce during the spring, with a male-female courtship ritual playing a large part in dolphin dating. To copulate the male dolphin nudges the female dolphin from behind with his sex organ for several minutes and then mounts her from behind. After this, dolphin mating is about the same as any other mammalian mating.
However to many people’s surprise, dolphins are among the most sexual animals on earth and are not monogamous. When aroused, a dolphin male may even mate several times an hour, often with the same female but not always. Due to the fact that dolphins are not monogamous, dolphin mothers usually rely on other female dolphins which act as “midwives” to help take care of and protect them and their calves.
After eleven or twelve months, female dolphins give birth to their young with the assistance of another female dolphin or “midwife”. Birth can happen anywhere and when it does the pod will often be seen surrounding her protectively while she is in labor as a way to defend the mother and calve and fend off any predators such as sharks who may be thinking about picking up a quick meal.
Baby dolphins are born tail first to avoid drowning, and are usually single births, with the exception of a few smaller dolphin species that have been known to give birth to two calves. During the birthing process, dolphin mothers help the calves to reach the surface by swimming beneath them and then gently lifting upward to get their first breath. Afterwards, the calves typically try to feed by finding the mammary glands located in the sacs toward the mother’s rear. Nursing has been known to generally continue anywhere from twelve to eighteen months.
Calves must eat quickly, as it is important for them to get back up to the surface to breathe. It is because of this that unlike most mammals that are equipped with a way to suckle their mother’s milk, dolphin mothers instead have specialized muscle contractions that squirt milk into the calves’ mouth. Dolphin calves grow very quickly on the high fat of their mother’s milk, and in some species have even been known to double in weight within a mere two weeks.
Dolphins are an interesting character and lack olfactory receptors (interestingly enough, the olfactory tract and bulb only exist in the fetal stage of development) therefore, it is true that dolphins do not have a sense of smell.
However though they lack in this department, it should not be assumed that they are not efficient in their other senses. In fact they have acute eyesight both in and out of water and they can hear frequencies ten times or more above the upper limit of adult human hearing. A dolphin’s sense of touch is also well developed, with free nerve-endings densely packed into the skin, especially around the snout, pectoral fins and genital area.
Something that is also very interesting is the fact that although dolphins lack a sense of smell, they do not lack a sense of taste as a result of not being able to smell. They also show preferences to certain kinds of fish opposed to others. Since dolphins spend most of their time underwater, tasting the water can function as smelling in that substances in the water can signal the presence of objects that are not in the dolphin’s mouth.
Yes, dolphins can and have been known to kill sharks. As many know, dolphins and sharks inhabit the same regions and depths of the ocean. Sharks have a reputation for being fierce predators, and are armed with rows of sharp nasty teeth that help them bite through flesh and bone with ease. They also have very tough, sandpaper- like skin that is not easily punctured. Whereas dolphins are often viewed as the intelligent, playful, friendly mammals with only a single row of peg-like teeth used mainly for catching smaller fish. Their skin, unlike the sharks is soft and flexible and can be punctured easily. Dolphins surprisingly, have however often been seen protecting an injured or sick member of their group or extended family, often from a shark attack. They have also at times been known to protect humans from sharks in the water and in some cases have even been known to carry a human safely to shore.
At first glance, sharks and dolphins may seem to be similar in size and shape, though sharks obviously appear to be stronger for obvious reasons already mentioned. However, when taking a closer look there are many differences in the two that can be noted and give the dolphin quite an advantage. Sharks are an ancient fish with skeletons of cartilage, where dolphins are descended from mammals that have returned to the sea and sport skeletons with hard, calcified bones. The skeletons of sharks have joints that are not as flexible as the dolphins.
It is for this reason that dolphins sometimes have the upper hand and are much swifter than sharks. They have also been known to maneuver very quickly and are very agile in the water. The tail of a shark is also different from a dolphin. A shark’s tail has a fins located on a vertical plane that move from side to side which limits its ability to quickly dive downward and /or rise upward. A dolphin’s tail however has horizontally mounted flukes that move up and down and enable a dolphin to change direction with ease, allowing it to move upward or downward with no problem.
Since dolphins normally travel together in groups, if one of the group is threatened by a shark, the other dolphins will join in without hesitation to do its best to defend the dolphin that is in danger. The dolphin’s main weapon against a shark attack is its snout, which is made up of very strong and thick bone and has a hard rounded end. The dolphins circle the shark rapidly from different directions thus confusing the shark and rendering it unable to chase any of the other dolphins.
When a dolphin is positioned below a shark at a distance of several yards, the dolphin will often make a sudden rush at the shark’s soft underbelly and ram it with its snout. The effect this has on the shark can be quite effective. It resembles a powerful punch and can seriously injure a shark with just one blow. When dolphins use this as their weapon against sharks, it often renders the shark stunned or knocks them unconscious immediately. Sometimes a dolphin will repeatedly ram a shark that has been aggressive in order to protect itself or its group, and in some cases have even been known to kill large and dangerous sharks. In most cases, even if the shark does not die as a result of the dolphin driving its snout into its underbelly, the force that it has on the shark will often leave some kind of internal damage.
What makes a mammal, a mammal are the several characteristics that particular animal has. For instance, all mammals have hair, as well as fat glands and sweat glands, female mammals also have mammary glands. All mammals are vertebrates and also have several types of teeth. Therefore, dolphins would not be classified as fish, they would be classified as mammals since they not only breathe air into their lungs, they have hair at some point during their life cycles, are warm blooded creatures, give birth to live young, and also nurse them with their mammary glands.