A Look At Dolphins for a 5th Grade Class By: Keith Innocenti

Dolphins Dolphins are mammals, not fish. They are warm blooded like man, and give birth to one baby at a time called a calf. At birth a dolphin calf is about 90-130 centimeters long and can grow up to 4 meters. Dolphins live in groups called pods.

The Dolphin’s Tail Dolphin’s tails are very powerful and can be used for many things. For Example: A dolphin will flap his tail in an up and down motion to move through the water. Other uses of the tail include hunting, stunning its prey, and slapping the water to warn other dolphins of danger.

The Dolphin’s Teeth The Dolphin’s teeth are very sharp in order to grab a hold of slippery fish. They have the ability to eat whole fish and usually do it head first. In the wild an open mouth for a dolphin is a sign of aggression, as is head nodding. A sign of greater aggression is violent jaw clapping.

The Dolphin’s Eyes The Dolphin’s eyes produce a slippery secretion that protects the eyes from foreign objects and water friction. When a dolphin sleeps it must shut down only half of its brain, as its breathing is under voluntary control. Dolphins are known to take very short cat-naps, floating just below the surface, then slowly rising to breathe.

A Dolphin’s Breathing Dolphins breathe through their blowhole located at the top of their head. A Dolphin may empty and refill its lungs in less than a fifth of a second. As the dolphin breathes the air leaves the blowhole at speeds of over a 100 mph.

The Blowhole Complex nerve endings around the blowhole sense pressure change so the dolphin knows exactly when the blowhole is in or nearing the air and can be opened. Water in a Dolphin’s blowhole will actually drown it, so powerful muscles close the blowhole as it dives under the water again.

The Dolphin’s Skin The Dolphin’s skin is completely smooth allowing the dolphin to move easily through the water, and also reduce heat loss. Their skin may bear rake marks from other dolphins teeth during playing or mating, and can easily become badly sunburned if they strand. Their bodies are very streamlined so they may swim at high speeds through the water, an example of this is their ears.

Great Depths Dolphin’s are able to dive to great depths, and also leap to great heights. They may use their leaping ability to avoid predators in the water or to show how powerful they are to females during mating time. Bottlenose dolphins can dive to depths of over 1,640 feet (500m).

Body Parts of a Dolphin

Food Intake Adult bottlenose dolphins eat approximately 4% to 5% of their body weight in food per day. Their stomach is made for rapid digestion. Dolphins eat a variety of fishes, squids, and crustaceans such as shrimps. The foods available to dolphins vary with its geographic location.

Life Expectancy The average life expectancy for a bottlenose dolphin is around 20 years. However, there have been cases of bottlenose dolphin’s living past 40. As A dolphin ages, it periodically produces growth layer groups of dental material. Age is estimated by examining a sliced section of a tooth and counting its layers.

Pictures Of Dolphin’s