Reptiles are cold-blooded animals that take on the temperature of their surroundings. Most reptiles have a three-chambered heart, though crocodiles have a four-chambered heart. Reptiles respire through lungs that are often divided into chambers with alveoli to increase surface area for oxygen absorption. They live on land or in water and have skin adapted for their environment, such as being watertight or having spines. Reptiles use camouflage and threatening displays as defenses, and some snakes use venom. Threatened crocodilians will hiss and inflate their bodies. Lizards can shed their tails to escape predators.

1. Vertebrata
(Reptilia)

2. Reptilia

3. Characteristics

4. Cold-Blooded animals
Cold-blooded creatures take on the temperature of their
surroundings. They are hot when their environment is hot and cold
when their environment is cold. In hot environments, cold-blooded
animals can have blood that is much warmer than warm-blooded
animals.

5. Heart
Many reptiles have a three-chambered heart consisting of two atria, one variably
partitioned ventricle, and two aortas that lead to the systemic circulation. The
degree of mixing of oxygenated and deoxygenated blood in the three-chambered
heart varies depending on the species and physiological state. Under different
conditions, deoxygenated blood can be shunted back to the body or oxygenated
blood can be shunted back to the lungs.
Exception: Crocodile- Four-chambered heart!

7. Respiration
All reptiles respire through lungs. The lungs of reptiles are large, and they are
often divided internally into several chambers. The lining of the lungs may be
folded into numerous small sacs called alveoli. Alveoli greatly increase the
internal surface area of the lungs, thus increasing the amount of oxygen that can
be absorbed. In most snakes, only the right lung actively functions. It is
elongated and may be half as long as the body. The left lung is either reduced to
a small nonfunctional sac or absent entirely.

9. Habitat
They are terrestrial or aquatic animals.

10. Skin
1)Water-Resistant-
Reptilian skin is covered in a horny epidermis, making it watertight and enabling
reptiles to live on dry land, in contrast to amphibians.
2) In some animals, their skin is modified to Spines for Protection.
3)Shedding- They shed their skin

11. Defense Mechanisms
• 1) Camouflage- Reptiles tend to avoid confrontation through camouflage. Two
major groups of reptile predators are birds and other reptiles, both of which
have well developed colour vision. Thus the skins of many reptiles have cryptic
colouration of plain or mottled gray, green, and brown to allow them to blend
into the background of their natural environmentAided by the reptiles'
capacity for remaining motionless for long periods, the camouflage of many
snakes is so effective most people or domestic animals most typically are
bitten because they accidentally step on them

12. A camouflaged Phelsuma deubia on a palm frond

13. Alternative defense in snakes
• Camouflage will not always fool a predator. When caught out, snake species
will adopt different defensive tactics and use a complicated set of behaviors
when attacked. Some will first elevate their head and spread out the skin of
their neck in an effort to look large and threatening. Failure of this strategy
may lead to other measures practiced particularly by cobras, vipers, and
closely related species, who use venom to attack. The venom is modified
saliva, delivered through fangs from a venom gland.

15. Defense in crocodilians
When a crocodilian is concerned about its safety, it will gape to expose the teeth
and yellow tongue. If this doesn't work, the crocodilian gets a little more agitated
and typically begins to make hissing sounds. After this, the crocodilian will start to
change its posture dramatically to make itself look more intimidating. The body is
inflated to increase apparent size. If absolutely necessary it may decide to attack
an enemy.

17. Shedding and regenerating tails
• Geckos, skinks, and other lizards that are captured by the tail will shed part of
the tail structure through a process called autotomy and thus be able to flee.
The detached tail will continue to wiggle, creating a deceptive sense of
continued struggle and distracting the predator's attention from the fleeing
prey animal. The detached tails of leopard geckos can wiggle for up to 20
minutes.
• Reptiles capable of shedding tails can partially regenerate them over a period
of weeks. The new section will however contain cartilage rather than bone,
and will never grow to the same length at the original tail..

19. Our Team Members
• Jerry George Jaimon (Leader)
• Shaun Saji
• Nithin Sam Cherian
• Kevin Babu
• Tobin Thanckachen
• Benjamin Jacob Reji
• Kyle Fernades
• Jobel Jose