Dolphin Bio Information

What are dolphins?

Dolphins, like you and me, are mammals.  They have teeth, are warm-blooded, have a four-chambered heart, and nurse their young from mammary glands. Dolphins also have hair — but not very much!

Dolphin Facts

The majority of small tooth whales are called dolphins.  They are mammals of the order Cetacea and the families Plantanistidae and Delphinidae and include about 50 species.  Cetaceans include all whales and dolphins. Some cetaceans, like the blue whale, are baleen whales and have horny plates hanging from their upper jaw that are used to strain food from the ocean.

All have a beak like snout and sharp, conical teeth.  The term porpoise is sometimes applied to many of the same species, but porpoises, are members of the family Phocaenidae and have a blunt snout and spade or chisel shaped teeth.  The dolphin fish, is neither a dolphin nor a porpoise.  It is a sport fish related to the mackerels.

Most dolphin species are about 6 ft in length, the males averaging 4 to 8 in longer than females.  The largest is the killer whale, which can be 19-22ft long and weigh between 8000-10000lbs.  One of the largest dolphins is the bottlenose dolphin which can reach over 9ft in length and weigh 440 lbs.  The smallest species is the buffeo, found in the Amazon River.  The buffeo rarely grows over 3.9 ft in length and 66 lbs in weight, really smalled compared to the bottlenose.

Scientific Classification

Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Cetacea
Suborder: Odontoceti
Family: Delphinidae
Genus: Delphinus
Species: Delphis

In the group of toothed whales, there are several subgroups:

Oceanic Dolphins: 33 Species
River Dolphins: 4 Species
Sperm Whales: 3 Species
Beaked Whales: 21 Species
Beluga and narwhal: 2 Species
Porpoises: 6 Species

Dolphin Species

Oceanic Dolphins

River Dolphins

Beaked Whales

Porpoises

Facts about Dolphins that you must know

1. Dolphins are mammals; therefore, they nurse their young from mammary glands.
2. Dolphins can swim up to 260 m. below the surface of the ocean, although they are mainly shallow divers.
3. Dolphins can stay up to 15 minutes under water, however they usually stay only a few minutes diving.
4. Dolphins use a technique called echolocation to find food and navigate.
5. Dolphins are social beings which live in groups and cooperate among each other for activities like getting food and calf rising.
6. There are 32 species of ocean dolphins and 4 species of river dolphins.
7. The largest dolphin is the “killer whale” (orca), which can grow 19 - 22 ft.
8. The most known dolphin is the “bottlenose dolphin” which can grow to 8 – 13 ft. length.
9. Dolphins are warm-blooded and their internal temperature is around 36 degrees. To conserve this temperature they are surrounded by a thick layer of fat called “blubber” just below the skin.
10. The average bottlenoses dolphin brain weighs 1500 - 1700 grs, while average human brain weighs 1300 - 1400 grs. This is not a conclusive evidence of dolphin intelligence as many other factors might be the cause of intelligence according to scientists.
11. Dolphins can make a unique signature whistle that may help individual dolphins recognize each other or perform any other kind of communication still unknown.
12. Bottlenose dolphins can swim 5 to 12 kilometers per hour, although they can reach up to 32 km/h.

How big do dolphins grow?

The biggest dolphin is the killer whale. Killer whale calves are about 8 feet long at birth and can grow to over 22 feet long. Bottlenose dolphins are about 3 1/2 feet long at birth and grow to 8 or 13 feet long.

Dolphin Anatomy & Physiology

Dolphins may look like fish, but they’re mammals that have adapted over the years to water. There are a number of differences caused by living in water instead of on land.

Dolphin Characteristics

a. Coloration and Skin

Bottle-nose dolphin's coloration is a non-descript gray to gray-green or gray-brown on the back, fading to white on the belly, lower jaw, and anal regions. The belly may be pinkish. This coloration, a type of camouflage known as counter shading, may help conceal a dolphin from predators and prey. When viewed from above, a dolphin's dark back surface blends with the dark depths. When viewed from below, a dolphin's lighter belly blends with the bright surface of the sea. Older animals in some regions sometimes show an inconspicuous spotting along their sides and on their bellies. A bottle-nose dolphin's skin is extremely delicate and easily injured by rough surfaces, making it very similar to human skin. Dolphin sheds its outer layer of skin about every two hours.

b. Pectoral flippers

A dolphin's forelimbs are pectoral flippers, which have all the skeletal elements of the forelimbs of terrestrial mammals, but they're foreshortened and modified. The skeletal elements are rigidly supported by connective tissue. Thick cartilage pads lie lengthwise between the bones. Pectoral flippers are curved slightly and pointed at the tips. Dolphins use their pectoral flippers mainly to steer and, with the help of the flukes, to stop.

c. Flukes

Each lobe of the tail is called a fluke. Flukes are flattened pads of tough, dense, fibrous connective tissue, completely without bone or muscle. Longitudinal muscles of the back and caudal peduncle (tail stalk) move flukes up and down to propel a dolphin through water. Dolphins propel themselves forward by moving their flukes up and down.

d. Dorsal Fins

Like flukes, the dorsal fin is made of dense, fibrous connective tissue, with no bones. The dorsal fin may act as a keel. It probably helps stabilize a dolphin as it swims, but is not necessarily essential to a dolphin's balance. There are some dolphin species lack dorsal fins. The dorsal fin is often falcate (curved back), although the shape is quite variable. It is located at the center of the back.

e. Head of Dolphin

A bottle-nose dolphin has a well-defined rostrum (snoutlike projection), usually about 3 inches long, marked by a lateral crease. Their teeth are conical and interlocking. They are designed for grasping (not chewing) food. The number of teeth varies considerably among individuals. Most individuals have 20 to 25 teeth on each side of the upper jaw and 18 to 24 teeth on each side of the lower jaw, a total of 76 to 98 teeth.

f. Eyes

Eyes are on the sides of the head, near the corners of the mouth. Glands at the inner corners of the eye sockets secrete an oily, jellylike mucus that lubricates the eyes, washes away debris, and probably helps streamline a dolphin's eye as it swims. This tearlike film may also protect the eyes from infective organisms.

g. Ears

Ears are located just behind the eyes, and are small inconspicuous openings, with no external pinnae (flaps).

h. Respiration a Single Blowhole

Oceanic dolphins have evolved a method of breathing without surfacing from the water. They blow a bubble when near the water surface and then quickly draw breath in when the bubble forms a bridge between the blowhole and the air, through the water. Dolphins breathe through their blowhole located at the top of their head which is covered by a muscular flap. The flap provides a water-tight seal. A dolphin may empty and refill its lungs in less than a fifth of second. As the dolphin breathes the air leaves the blowhole at speeds of over 100mph. When the dolphin is relaxed the blowhole is in a closed position, to open the blowhole, the dolphin must contract the muscular flap. To sleep, a dolphin must shut down only half of its brain, as its breathing is under voluntary control.

Dolphin Senses

Imagine a world of darkness and sudden light, a world in which you can move not only side to side but up and down as well, a world without a bottom to it but instead a top to which you must periodically rise.

a. Hearing

Dolphins have a well-developed, acute sense of hearing. The hearing range of a bottlenose dolphin respond to tones within the frequency range of 1 to 150 kHz. (The average hearing range for humans is about .02 to 17 kHz.) Unlike humans, a dolphin's inner ear is encased in a separate bone, called auditory bulla (earbone complex), which is connected to the skull with fibrous tissue. Thus, the bulla is essentially isolated from the skull, and sound enters the ear most efficiently through the jaw and middle ear.
A fat-filled cavity in the lower jawbone appears to conduct sound waves through the jaw to bones in the middle ear. The specialized anatomy of the dolphin's ear probably allows it to localize sounds under water effectively, a task that is difficult for humans. A dolphin's middle ear cavity is filled with a highly vascularized (supplied with blood) tissue. When a dolphin dives, this tissue helps adjust pressure on the middle ear. As stated before a dolphin has small external ear openings, a few inches behind each eye. Each opening leads to a reduced ear canal and an eardrum.

b. Eyesight

Dolphins have acute vision both in and out of the water. A dolphin's eye is particularly adapted for seeing in water. In air, certain features of the lens and cornea correct for the refraction of light caused by the transition from aquatic to aerial vision. Without this adaptation, a dolphin would be nearsighted in air.

The retinas of odontocetes have two central areas that receive images (human eyes only have one). Due to this feature of the retina, bottle-nose dolphins have binocular vision in air, and may have both binocular and monocular vision under water. A dolphin's retina contains both rod cells and cone cells, indicating that they may have the ability to see in both dim and bright light. (Rod cells respond to lower light levels than cone cells do.) The presence of cone cells suggests that dolphins may be able to see color, although studies have not actually determined this yet.

Dolphin's eyes have a well-developed tapetum lacidum, a light-reflecting layer that reflects light through the retina a second time, giving them enhanced vision in dim light.

c. Tactile

A dolphin's skin appears to be sensitive to a broad range of tactile sensations. Dolphins are quite sensitive to touch, and spend a good deal of time touching and caressing each other. Free nerve endings are densely packed in the skin, especially around the snout, nipple, genital regions, and parts of the pectoral fin. These are all areas of frequent contact among dolphins. There sense of touch may enable dolphins to detect subtle differences in the water pressures surrounding their bodies. This would explain their ability to maneuver among obstacles with such grace and ease.

d. Taste

Bottle-nose dolphins do have taste buds, although they haven't been extensively studied. They are capable of detecting waterborne chemicals through their sense of taste.

Researchers suggest that a dolphin might obtain information by tasting the trails of both urine and feces from other dolphins. These may contain sexual pheromones, indicating the sexual state and perhaps the identity of an individual. Tasting the trails may also enable dolphins to track companions over distances.

Dolphins show strong preferences for certain species of food fishes. However, this may have more to do with the texture of the fish, rather than taste.

e. Smell

This is the only sense among dolphins that is lacking. Olfactory lobes of the brain and olfactory nerves are absent in all toothed whales, indicating that they have a limited sense of smell.

Dolphin Feeding

Since wild dolphins catch and eat their food underwater and research is expensive and often hard to do, most of the data regarding their feeding habits has come from analyzing the contents of the stomachs of dead animals that wash up on the beach. Dolphins feed on live food and are predators, except when trained otherwise in captivity.  The primary food is fish, mostly things like herring, mackerel, and sardines.  Some species seem to prefer squid, occasionally, shrimp and other crustacean are consumed, and even mollusk shells have been found in their stomach contents.  Food consumption is estimated at about 66 lb a day for an individual about 8.2 ft in length and 220 lb in weight.

Reproduction

Reproduction of dolphins closely resembles that of land mammals. Sometimes dolphins can court or play for days. They swim together and pet each other with their fins. The actual mating is brief and it lasts only one to two seconds. Reproduction normally occurs during the spring months.

Males make elaborate swimming patterns and calls. Whether this is done to show off their fitness or to show other dolphins that he has coupled with a female is unknown. Females have a short period in every few years when they are fertile.

Gestation takes between 11 to 12 months. Gestation is how long the female dolphin is pregnant. The delivery of the baby dolphin is usually tail first, because if the calf is born head first, it won't be able to get to the surface in time to breath, and will suckle from its mother for up to 4 years. Newborn calves can be seen swimming near their mothers head for about a week before they swim nearer to her dorsal fin. This is termed as echelon swimming.

Female dolphins can retain the ability to produce milk long after they lose the ability to make babies. Inexperienced females will care for the calves of other females to gain experience.

Mature female dolphins will give birth every 2 to 3 years and could give birth as many as eight times during their lifetimes. Females mature sexually at 8 years of younger and dolphins are sexually promiscuous with males competing for females.

But the birth of a dolphin starts long before his babyhood; it starts with how Mom and Dad first met.

Communication

Because dolphins are highly social and vocalize among themselves with a wide range of sounds, it has been conjectured that they might possess and almost human like intelligence.  In the 1950s and '60s the American neurologist John Lilly conducted well publicized experiments based on this concept, in which he attempted to communicate with dolphins in their own language, but other scientists have rejected his work as poorly documented and lacking scientific validity.

Because of the ability of dolphins to learn and perform complex tasks in captivity, their continuous communications with one another, and their ability, through training, to approximate the sounds of a few human words, some investigators have suggested that the animals might be capable of learning a true language and communicating with humans.

a. Dolphin Language
Dolphins are like the kid that won’t shut up. They are almost constantly making sounds of one of two kinds: communicative or navigational. The different sounds are made in different ways.

b. Dolphins Sounds and Acoustics
Dolphin sounds and acoustics. Most people have heard the chirping, squeaking noises made by dolphins which they use to communicate with dolphins and human trainers and to navigate by using echolocation, or figuring out where things are by bouncing sound off them.

c. Dolphin Echolocation
Echolocation is a technique used by some animals to detect objects in the environment, like other animals, food and obstacles. Bats use it in the air and dolphins use it in the water

To echolocate, the dolphin generates a sound pulse (of clicks) in its forehead which is sent into the water. The sound bounces off objects, creating an echo that returns to the dolphins. We think that dolphins hear the returning echoes by feeling the sound pulses against their jaws. Different objects (like different kinds of fish) give off different kinds of echoes. Dolphins can also judge how far away the object is by the amount of time it takes for the echo to return.

Intelligence

Dolphins are highly intelligent animals with complex social structures. The first several years of a baby dolphins life is spent very close to his mother watching and learning everything from her and his/her other elders. Everything from navigating and traveling in new areas, hunting different species of fish, and even social skills are learned behaviors. It is because of this that researchers are beginning to study cultural differences in dolphin pods around the world. Just as it is known that pods of orca whales from different areas have distinct dialects, the same applies to other cetaceans and their habits.

One such indicator is that of self-awareness. Bottlenose dolphins have been shown to be able to recognize themselves in a mirror, a behavior that until recently has only been recorded in humans and great apes. Similarly, tool use can be seen as a mark of intelligence. In a masterstroke of innovation, some Indo-Pacific bottlenose dolphins carry sponges on the ends of their beaks to protect them when foraging for food on the sea bed.

Evidence of the typically human emotions, grief, parental love and joy, as well as the existence of complex social interactions and structures, are further indicators of the highly developed intelligence of dolphins.

Research on bottlenose dolphin intelligence is continuing.

Range

Dolphins can be found in virtually all the seas and oceans of the world.  Some species are sharply restricted, but many, like the common dolphin, Common Dolphin -Delphinus delphis-, or the Bottlenose dolphin, are found worldwide.  Several species are found in fresh water, notably the Ganges River dolphin -Platanista gangetica-; the rivers of South America are the home of the long-snouted dolphin -Inia geoffrensis-, and the small, graceful Sotalia fluviatilis, occasionally seen as far as 1,553 miles up the Amazon River.

Dolphins are quite abundant in some areas of the world.  Off the coast of Japan, for example, populations of the white-sided dolphin are estimated at 30,000 to 50,000 individuals.  In many species, schools of up to 1,000 travel together, while some species, such as the bottlenose dolphin, tend to be found in smaller groups of less than 100.

Variations in water temperature, migration of food fish, and feeding habits may account for the seasonal movements of some dolphins to and from certain areas

Some coastal dolphins in higher latitudes show a clear tendency toward seasonal migrations, traveling further south in the winter. Those in warmer waters show less extensive, localized seasonal movements.

Dolphins and Humans

Dolphins have been interacting with humans for as long as we have known of their existence. They adapt well to human companionship and as stated before are easily trained to perform complex tricks and tasks. Bottlenose dolphins have become well known performers in many aquariums. We like to think that dolphins enjoy being around us as much as we do them. Is it possible that dolphins share our company simply for diversity? Some species can become bored with their own kind. Who gets more out of the relationship: the human or the dolphin? Dolphins provide us with insight into the realms of anatomy, behavior and communication. Still, our curiosity pushes us to learn more. Although we admire other animals, dolphins remain high on our list of species that fascinate us.

When most people think of dolphins, they think of Flipper from television and film. Words like playful, intelligent, loving and friendly pop into our heads. They are seen as the aquatic version of man's best friend. Although there are many instances of dolphins being friendly, we need to remember that dolphins are wild animals. While humans seek them out, they usually avoid human contact.

During all this time, their more ferocious predators and the ones that have reduced more dramatically dolphin population are humans.

Having a deeper knowledge and information about dolphins is the first step towards a better conservation and understanding of these wonderful mammals. Also, this information is our weapon and our little contribution to fight dolphin killing and habitat damage.

Dolphin Predators
Dolphins are not chicken of the sea; yet it would appear that they make a tasty meal for many predators. And why not? With an exceptionally high fat content, dolphin and other cetacean meat provides great nutrition for predators who stalk, or swim stalkingly, throughout the ocean.

Wild Dolphins
As Swim with the Dolphin programs and Dolphin Assisted Therapy (DAT) continue to gain popularity; we're seeing more and more dolphins being held in captivity than ever before. While some scientists claim that dolphin research is progressing in great strides, critics believe that holding wild dolphins captive is cruel and should be stopped

Dolphins in the Military
Dolphins in the military. We've heard for years that Dolphins are incredibly intelligent creatures. It turns out that they are even intelligent enough to serve in the United States Navy, and have been doing so since 1960.

Dolphins in Mythology
Dolphins in Mythology. Dolphins have been viewed as somehow magical for millennia by humans. They’re one of the only animals that appear to play, leaping out of the water and doing tricks, and the bottlenose dolphin even seems to grin widely at everything.

Dolphin Assisted Therapy
Dolphin Assisted Therapy. Originating in 1978 by Dr. David Nathanson, Dolphin Assisted Therapy (DAT) has been used as a therapeutic approach to increase speech and motor skills in patients who have been diagnosed with developmental, physical, and/or emotional disabilities, such as mental retardation, Down syndrome, and autism.

Are all dolphins endangered?

No, all dolphins are not endangered. Neither the bottlenose dolphin nor the killer whales are endangered. However, several of the river dolphins are very endangered because humans have destroyed their habitat. If we humans don't take care of the earth, many more species of dolphins will become endangered in the future.

Endangered dolphins are a huge concern in our actual society. Why is it a problem? Well, first of all, if such specie like the dolphin is endangered, it means that if this situation is not dealt with properly, soon we might see their specie disappear from our oceans.

What kind of problem could this create for both their environment and their ecosystem? This would create a huge imbalance in the food chain. No dolphins to eat some creatures then there would be too many. Too many of them means less food for each one and since their food might be marine plants, they will not grow fast enough to feed everyone.

As a result, both former dolphin's preys and the plants will gradually disappear as well. Is it really the kind of environment that we want to leave to our children?

That is why endangered dolphins must be well protected by environmental laws such as the laws protecting common dolphins.

Why are dolphins endangered? There are three main reasons why dolphins are endangered and all of them are related to humans.

The first reason is since both tuna and dolphins follow the same routes, dolphins get caught in the fishermen's nets which are meant to catch tuna. In this case, they get fatally hurt or they drown as a result of it.

The second reason is fishing for use in human's cuisine. Nowadays, dolphins are protected by laws but nonetheless between 200,000 and 500,000 dolphins were victimized by fishermen during the 1960-1972 years. Also, even if some laws protect dolphins, it allows a certain amount of dolphins to be accidentally caught which still has a negative impact on the dolphins' species.

The last but not least is pollution. Since humans are polluting rivers, seas and oceans, it affects dolphins. Also, since the dolphin is at the top of the food chain, the chemicals that pollute its habitat create the highest level of concentration of these pollutants in its body. As a result, diseases, difficulty to reproduce or even death take their toll on these species.

The endangered dolphins' species are: Baiji or Yangtze river Dolphin, is now almost certainly extinct;the world's most critically endangered cetacean species now is the vaquita or Gulf of California porpoise, of which 250 survive.

Other endangered specie according to the International Union for Conservation of Nature and Natural Resources, there are only about 50 Maui’s dolphins currently alive. "The Maui’s dolphin is the world’s rarest marine dolphin," said World Wildlife Fund - New Zealand Chief Executive Jo Breese.

If you want to read more about the conservation efforts to protect the endangered dolphins, visit : http://www.worldwildlife.org/who/media/press/2005/WWFPresitem798.html

Check list ECO WILD DOLPHIN TOUR

Why Come and See Dolphins in the Wild?

There is a big difference between the tank environment captive dolphins and their natural environment!

Dolphins are intelligent and social creatures that, in the wild, interact with hundreds of pod-mates, hunt communally, and have entire coastlines as their playground. In captivity, all of this is lost. Social partners are restricted to a handful of tank-mates. Captive dolphins are fed dead fish (wild dolphins only catch and eat live fish; they never eat dead fish) and they face a profound reduction in space and stimulation.

Dolphins in the wild may swim up to 40 or 50 miles in a day and can dive to depths of hundreds of feet. Even in the largest facilities, captive dolphins have access to less than 1/10,000 of 1% (0.000001) of the space available to them in their natural environment. Dolphins in captivity are often restricted to swimming in circles. In many dolphins, this behavior is a sign that the dolphin is suffering psychologically; it is engaging in what is known as a stereotypical behavior. For an inquisitive, intelligent creature like the dolphin, a barren tank offers no exploratory stimuli compared to the vast, complex ocean.

So, be part of an environmental group “Ecotours” will be waiting for you to take part of the rescue of our world lovable creatures “Dolphins”.