Living reptiles comprise what?
A: Turtles, crocodilians, squamates (lizards and snakes) and rhynchocephalians (tuatara).
As of March 2022, the Reptile Database includes how
A: About 11,700 species.
In the traditional Linnaean classification system,
birds are considered what?
A: A separate class to reptiles.
The study of the traditional reptile orders,
historically combined with that of modern amphibians, is called what?
In addition to the living reptiles, there are many
diverse groups that are now extinct, in some cases due to what?
A: Mass extinction events.
Modern non-bird reptiles inhabit all the continents
Reptiles are tetrapod vertebrates, creatures that
either have four limbs or, like snakes, are what?
A: Descended from four-limbed ancestors.
Unlike amphibians, reptiles do not have what?
A: An aquatic larval stage.
The origin of the reptiles lies about 310–320 million
years ago, in what?
A: The steaming swamps of the late Carboniferous period, when the first reptiles evolved from advanced
As in all animals, reptilian muscle action produces
In large reptiles, like leatherback turtles, the low
surface-to-volume ratio allows this metabolically produced heat to do what?
A: To keep the animals warmer than their environment even though they do not have a warm-blooded metabolism.
A crocodile needs from a tenth to a fifth of the
necessary for a lion of the same weight and can live how long without
A: Half a year.
Lower food requirements and adaptive metabolisms allow
reptiles to dominate the animal life in what type of regions?
A: Regions where net calorie availability is too low to sustain large-bodied mammals and birds.
Most extant reptiles are carnivores with what feeding
A: A sit-and-wait.
All reptiles breathe using what?
Aquatic turtles have developed what?
A: More permeable skin, and some species have modified their cloaca to increase the area for gas exchange.
Most reptiles lack a secondary palate, meaning that
they must do what?
A: Hold their breath while swallowing.
Crocodilians have evolved a bony secondary palate that
allows them to continue breathing while what?
A: While remaining submerged (and protect their brains against damage by struggling prey).
Snakes took a different approach and instead, extended
A: Their trachea.
Their tracheal extension sticks out like a fleshy straw
and allows these animals to do what?
A: Swallow large prey without suffering from asphyxiation.
Compared with frogs, birds, and mammals, reptiles are
Sound production is usually limited to what?
A: Hissing, which is produced merely by forcing air though a partly closed glottis and is not considered to be a true vocalization.
The ability to vocalize exists in crocodilians, some
lizards and turtles; and typically involves what?
A: Vibrating fold-like structures in the larynx or glottis.
Some geckos and turtles possess true vocal cords, which
A: Elastin-rich connective tissue.
Unlike humans and other animals, snakes do not possess
A: An outer ear, a middle ear, and a tympanum but have an inner ear structure with cochleas directly connected to their jawbone.
They are able to feel the vibrations generated from the
sound waves in their jaw as they do what?
A: Move on the ground.
This is done by the use of mechanoreceptors, sensory
nerves that run where?
A: Along the body of snakes directing the vibrations along the spinal nerves to the brain.
Snakes have a sensitive auditory perception and can
A: Which direction sound being made is coming from so that they can sense the presence of prey or predator.
Reptilian skin is covered in a horny epidermis, making
it watertight and enabling reptiles to live on what?
A: Dry land, in contrast to amphibians.
Compared to mammalian skin, that of reptiles is rather
thin and lacks the thick dermal layer that does what?
A: Produces leather in mammals.
Exposed parts of reptiles are protected by what?
A: Scales or scutes, sometimes with a bony base (osteoderms), forming armor.
In lepidosaurians, such as lizards and snakes, the
whole skin is covered in what?
A: Overlapping epidermal scales.
The scales found in turtles and crocodiles are of
dermal, rather than epidermal, origin and are properly termed what?
In turtles, the body is hidden inside a hard shell
composed of what?
A: Fused scutes.
Lacking a thick dermis, reptilian leather is not what?
A: As strong as mammalian leather.
It is used in leather-wares for what?
A: Decorative purposes for shoes, belts and handbags, particularly crocodile skin.
Reptiles shed their skin through a process called what?
A: Ecdysis which occurs continuously throughout their lifetime.
In particular, younger reptiles tend to shed once
every how often?
A: 5–6 weeks while adults shed 3–4 times a year.
Younger reptiles shed more because of what?
A: Their rapid growth rate.
The process of ecdysis involves forming what?
A: A new layer of skin under the old one.
Proteolytic enzymes and lymphatic fluid is secreted
A: Between the old and new layers of skin.
Consequently, this lifts the old skin from the new one
A: Shedding to occur.
Snakes will shed from the head to the tail while
lizards shed how?
A: In a "patchy pattern".