The available research demonstrates that sea turtles are among the most ancient creatures on the planet earth. Studies indicate that they have existed for about 110 million years (Defenders of Wildlife) and are unique in various ways, that is, in comparison to other turtles. First, they do not have a standard body color as some of them are greenish, others yellowish, and some brownish. Secondly, they cannot fold or retract their head and legs into shells as other turtles do (Seaturtle-world.com).
Sea turtles belong to class reptilia, order testudines, and family cheloniidae (Entertainment).
Habitat, Distribution, and Population
There are various species of sea turtles, each with a specific habitat and distribution point. However, in general, sea turtles are available in warm and moderate sea across the world. Loggerhead sea turtles, as evidenced by research, are the only sea turtles found globally - most species have specific locale. The population of sea turtles is increasingly declining mainly due to pollution and changing weather patterns.
Sea turtles vary in size and weight depending on their species (Seaturtle-world.com). For instance, leatherbacks are the largest while olive ridleys are the smallest. The average weight of a leatherback ranges from 200-600kg while that of an olive ridley spans from 30-50kg. Concerning weight, males and females have slightly different weights, almost insignificant. Sea turtles have a large streamlined shell, which varies in color and shape. Their limps are weak on land as they are in essence for swimming. When young, it is quite impossible to distinguish between males and females as such differences begin to show up in adulthood (Entertainment). Adult males have longer tails in comparison to females.
Sea turtles are moderately social creatures. There are incidences when they gather offshore. Much of their coming together arises when they want to mate. These organisms rarely come out of water. Usually, they spend most of their time floating on water, probably sleeping or enjoying the sun.
Their diet varies depending on their species. Some are carnivorous, others omnivorous, and the remaining herbivorous. For example, green sea turtles are solely vegetarians while loggerheads are omnivorous. Regardless of the species, sea turtles generally feed on soft meals.
Sexual maturity varies depending on the species. For instance, loggerheads reach maturity as from 12-30 years while green sea turtles reach maturity as from 20-50 years. Fertilization is naturally internal and copulation takes place in water (Orf.org). Nesting takes place during the warmest months of the year, most likely March-October. Other species, for instance, leatherbacks do their nesting in winter. The gestation period of sea turtles varies from 6-10 weeks.
Galapagos Giant Tortoises
They are the largest existing tortoises on the planet earth. Everything about them is unique, from their length to the size of their different body parts to their lifespan. They belong to kingdom Animalia, phylum Chordata, class reptilia, order testudines, and family testidunidae. Besides having a long lifespan, they keep growing up to about 40-50 years. Research indicates that they can live for more than 100 years (Society). According to research, these creatures belong to one species known as Geochelone elephantopus. Of this species, studies indicate that there are 14 subspecies within it, three of which are extinct.
These tortoises have heavy and large limbs, long necks, and heavy shells. They have varying body colors depending on their species. Some are brownish, others reddish, and another grayish. They have an average length of 1.2 meters, although some exceed 1.5 meters. Adult tortoises have a standard weight of 255-310 kg (Arkive.org). Depending on the genus, Galapagos tortoises have either domed shells or saddleback shells.
Their habitat preference varies depending on their adaptation. Domed shelled tortoises mostly reside in cool, watery, and densely filled ground vegetation areas. Saddleback shelled tortoises live in live in warm, drier, and sparsely populated ground vegetation.
Galapagos tortoises are herbivorous. They feed on a variety of vegetation including fruits, vines, cactus, and grass. These creatures have the ability to store food and water for long periods. This implies that they can go for long durations without food. Additionally, they can survive for long without water due to their ability of breaking down stored fats into water.
In view of the fact that they are cold-blooded animals, they spend most of their daytime soaking in the sun. Naturally, they are slow creatures, estimated to be moving at a speed of about 0.3km/h. However, when in danger, or when targeting something, they can move at incredible speeds. Apart from being peaceful animals, these creatures relate well with other species. For example, flycatchers often use their backs as observation points from which to trap their prey. Their good relationship with other creatures such as Galapagos Hawk likewise protects them from harmful parasites.
Mating usually takes place between January and August. After mating, females have to find nesting areas, often close to sea shores. Building of nests takes long, from one hour to several days. Females use their hind limbs to dig holes of about 0.3m deep. After which, they place eggs and cover up the place. Eggs often hatch after 3-4 months and the newborns may weigh 0.08kg. It is important to state that temperature plays an important role in the determination of sex. Low temperatures result in more males while high temperatures result in more females.
The most notorious predators of Galapagos tortoises are hawks and humanity. Potential threats to their food supply include rats, goats, sheep, dogs, and cattle.
Galapagos tortoises are mainly available in Ecuador. Their numbers continue to decline due to changing weather patterns, pollution, and poaching. Today, there are about 15,000 of them.
Galapagos tortoises have several adaptation features and techniques. Saddleback tortoises have long necks, which in turn makes it easy for them to be able to reach taller vegetation. They likewise have a low metabolism rate, in that way, are able to store water and food for long durations. Their long necks enable them to solve disputes among themselves, which they do by raising their heads. In contrast, domed tortoises have short necks as they reside in environments of abundant vegetation. In consequence, they do not need to lift their heads to eat (AMNH). Galapagos tortoises often have difficulties reaching their entire body. For that reason, they have to rely on other creatures such as mocking birds to purge parasites from them. Usually, birds come close to them, and once ready, they stretch out their necks for birds to access the otherwise inaccessible areas. Their large sizes make them unattractive to most predators. In this way, they are able to survive for long. Lastly, their gigantic size offers them immunity against extreme temperatures (Edangalapagostortoise.wikispaces.com).
Sea turtles have powerful jaws that enable them to digest their prey. Inside their throats, they have a leathery projected line, which shields them from the stings of other sea creatures. These organisms have specialized glands within their bodies for metabolism of saltwater. During nesting, females produce watery-like tears, which in turn prevent sand from entering their eyes. In consideration of the fact that they are ectothermic, they are able to lower their metabolism rate, in this way, are able to remain submerged in water for long periods. The color of their carapaces helps them to hide from their predators. Lastly, their bodies are drag resistant, implying that they hardly encounter difficulties in navigation.
Galapagos tortoises generally fall into two groups – namely, domed and saddleback tortoises. The main difference between the two is that one category has short necks while the other long necks. Scientists attribute the difference to environmental adaptation. Galapagos tortoises that resided in dry areas had to develop long necks to be able to reach their meal while those that resided in abundant vegetation had no need to have long necks. On the other hand, sea turtles, unlike most turtles, cannot retract their limbs and head. According to research, retraction would have had a tremendous impact on their navigation. Additionally, their forelimbs have increasingly with time become like paddlers, in this way, increasing their cruising speed. Finally, their shells, due to their varying colors, have continued to protect them from predators. In reality, their shells make them look like sea corals.
AMNH. "Galapagos Tortoises and Evolution". 2016. Web. 6 Jan. 2016.
Arkive.org, "Galapagos Giant Tortoise Videos, Photos and Facts - Chelonoidis Nigra | Arkive". 2016. Web. 6 Jan. 2016.
Defenders of Wildlife, "Basic Facts about Sea Turtles". 2012. Web. 6 Jan. 2016.
Edangalapagostortoise.wikispaces.com. "Galapagostortoise - Galápagos Tortoise". 2016. Web. 6 Jan. 2016.
Entertainment, SeaWorld. Seaworld.org. 2016. Web. 6 Jan. 2016.
Orf.org. "The Oceanic Resource Foundation: Underwater Photography / Marine Conservation". 2016. Web. 6 Jan. 2016.
Seaturtle-world.com. "Sea Turtle Facts, and Information". 2016. Web. 6 Jan. 2016.
Society, National. "Galápagos Tortoises, Galápagos Tortoise Pictures, Galápagos Tortoise Facts - National Geographic". National Geographic. 2016. Web. 6 Jan. 2016.