Reptiles are air-breathing vertebrates covered in special skin made up of scales, bony plates, or a combination of both. They include crocodiles, snakes, lizards, turtles, and tortoises. All regularly shed the outer layer of their skin. Their metabolism depends on the temperature of their environment.
In total there are around 118 species of reptiles in Florida, including both native and introduced species. Three out of the four orders of reptiles can be found in Florida, with the Tuatara order being absent.
Unlike birds and mammals, reptiles do not maintain a constant internal body temperature. Without fur or feathers for insulation, they cannot stay warm on a cold day, and without sweat glands or the ability to pant, they cannot cool off when it’s hot. Instead, reptiles move into the sun or into the shade as needed. During cooler parts of the year they become inactive. Due to their slow metabolism and heat-seeking behavior, reptiles are cold-blooded.
Information & Facts:
Most reptiles have a continuous external covering of epidermal scales. Reptile scales contain a unique type of keratin called beta keratin; the scales and interscalar skin also contain alpha keratin, which is a trait shared with other vertebrates. Keratin is the main component of reptilian scales.
Scales may be very small, as in the microscopic tubercular scales of dwarf geckos (Sphaerodactylus), or relatively large, as in the body scales of many groups of lizards and snakes. The largest scales are the scutes covering the shell of a turtle or the plates of a crocodile.
The diversity of reptile life histories is amazingly wide and often reveals nearly unimaginable reproductive adaptations. Some reptiles are annual species that hatch, mature, reproduce, and die in one year or, at most, two years (as in side-blotched lizards [Uta stansburiana]). Others, such as loggerhead sea turtles (Caretta caretta), are long-lived species that require 25 or more years to mature and have life spans that exceed 50 years.
Numerous other species fall between these extremes. Some reptiles lay eggs, whereas others are live-bearers. Some species lay 1 or 2 eggs, whereas others lay 100 or more eggs in each nesting event. Some reptiles nest year round, whereas others may nest once each year or allow two or more years between breeding cycles.
The skeletons of reptiles fit the general pattern of vertebrates. They have a bony skull, a long vertebral column that encloses the spinal nerve cord, ribs that form a protective bony basket around the viscera, and a framework of limbs. Each group of reptiles developed its own particular variations on this major pattern in accord with the general adaptive trends of the group.
Snakes, for example, have lost the limb bones, although a few retain vestiges of the hind limbs. The limbs of several types of marine reptiles have been modified into fins or flippers. In other types, the bones of the limbs, which no longer needed to support the weight of the body against the pull of gravity, became much shorter. At the same time, the bones of other reptiles that composed the digits multiplied in number, forming a long flipper.
Groups of reptiles whose modes of life depend heavily on passive defense also have developed specializations of the skeleton. The bony and horny shells of turtles and the rows of bony plates on the backs of crocodiles are examples of this.