Dolphin
Cortlyn Harris, 1st period, May 16th, 2016
Habitat
All but five of the 34 dolphin species live in tropical and temperate oceans. Five species live in rivers(Defenders of Wildlife Kids' Planet). Marine mammals are found in all oceans of the world and in a few rivers(Wood, Lisa) Obviously you know they live in water. I bet you didn't know they live in some rivers.
Movement
Many species will leap out of the water, spy hop(rise vertically out of the water to view their surroundings(Defenders of the Wildlife Kids' Planet). Mammals are a group of vertebrates(animals with backbones) that share common traits(Wood, Lisa) Dolphins listen for an echo to tell them the location of things in their watery world. And not just location. They can also sense size, shape, and texture. With echolocation, a dolphin can know that there is a three-inch steel ball 100 yards away, or that a single teaspoon of water is being dropped into its tank.(Rahm, Linda) They also move their fin up and down, not side-to-side. If they do that it could harm their fin, jeopardizing their ability to swim. I found that out by watching The Dolphin Tale.
Body Covering
..have sweat glands in their skin to help them cool off. Sweat glands give off water mixed with salts and other waste products. Sweat cools the skin when it evaporates off its surface. But some mammals don't sweat very much(Brusso, Charlene). A dolphin's skin may seem slick and smooth to the touch, but if you look at it through a powerful microscope, you will discover that it is actually covered with tiny grooves. These rippled channels run from nose to tail and help the dolphin slip more easily through the roughest waters. The grooves also protect the dolphin by preventing marine parasites from attaching to its skin(Brusso, Charlene). They are also warm-blooded. Which means they slow down in the cold seasons.
Diet
They like to eat slimy fish and medium sized squid. They are Carnivores and aren't that big on other prey. They have 40-55 pairs of small pointed teeth in each jaw--a long-beaked common dolphin can have as many as 200 teeth! These are ideal for grasping the slippery fish and squid they like to eat(Bailey, Amanda) Their teeth are pretty strong but are not strong enough to beat other water mammals.
Reproduction
They breed throughout the year in warm tropical waters and give birth in late spring/early summer in cooler regions. The females are pregnant for ten to 11 months. They give birth to a single calf, usually every two years, and they can live for 40 years. At birth the calves are about 85cm long and weigh 11kg; they feed on their mother's milk until they are six months old, when they add fish and squid to their diet(Bailey, Amanda). They do not give birth to more than one dolphin, they can but the process would have to start up again.
Adaptions
Using echolocation to find prey, dolphins eat a variety of food including fish, squid and crustaceans. Dolphins often hunt together, surrounding a school of fish, trapping the fish, and taking turns swimming through the school and catching fish. Dolphins will also follow seabirds, other whales and fishing boats to feed opportunistically on the fish they scare up or discard.(Defenders of Wildlife Kids' Planet)
Other Info
- Dolphins' eyes are set well back on the side of their head, and because their beaks are pointed, they have a good view of what is in front and below
- Dolphins are cetaceans, like whales and porpoises, so are not fish, but mammals and need to breathe air, just like us
- Extremely active, fast moving and playful
- Many are killed each year in fishing nets(Bailey, Amanda)
- Dolphins prefer to eat Opal Squid
- Found all over the world; in oceans
- The move in pods.
Works Cited
Bailey, Amanda. "Common Dolphins." Sirs Discoverer. Ed. Animal Action. N.p.:
n.p., 2003. 21-23. SIRS Discoverer. Web. 13 May 2016.
<http://discoverer.prod.sirs.com/discoweb/disco/do/
article?urn=urn%3Asirs%3AUS%3BARTICLE%3BART%3B0000177418>.
n.p., 2003. 21-23. SIRS Discoverer. Web. 13 May 2016.
<http://discoverer.prod.sirs.com/discoweb/disco/do/
article?urn=urn%3Asirs%3AUS%3BARTICLE%3BART%3B0000177418>.
Defenders of Wildlife Kids' Planet. "Dolphins." Sirs Discoverer. By Sirs
Discoverer. N.p.: n.p., 2005. N. pag. SIRS Discoverer. Web. 13 May 2016.
<http://discoverer.prod.sirs.com/discoweb/disco/do/
article?urn=urn%3Asirs%3AUS%3BARTICLE%3BART%3B0000242644>.
Wood, Lisa. "Marine Mammals." Sirs Discoverer. N.p.: n.p., 2008. 34-53. SIRS
Discoverer. Web. 13 May 2016. <http://discoverer.prod.sirs.com/
discoweb/disco/do/article?urn=urn%3Asirs%3AUS%3BARTICLE%3BART%3B0000299887>.