Reptiles - Characteristics of Reptiles

len Alfred Ajibola - Tue, 16th April, 2019 @ 8:32 PM

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Academic Questions in Biology

Please click here to see all Questions and Answers

Male Reproductive System - Len Academy

From the above diagram, which of the organ below isn't a requirement for the male reproductive system?

  • A. Bladder

  • B. Ureter

  • C. Glans Penis

  • D. Testis

  • E. Bulbourethral Gland

  • F. Epididymis

A walnut shaped male accessory sex organ located between the bladder and penis is the _____.

  • A. Ductus Ejaculatorii

  • B. Bulbourethral Gland

  • C. Prostate Gland

  • D. Ductus Deferens

  • E. Seminal Vesicles

  • F. Epididymis

In a food chain, the primary consumers are classified under trophic level  _____.

  • A. Zero

  • B. One

  • C. Two

  • D. Three

  • E. Four

  • F. Five

Cold blooded animals are referred to as _____.

  • A. Homeotherms

  • B. Endotherms

  • C. Poilokitherms

  • D. Ectotherms

  • E. Thermotherms

  • F. None of the above

All reptiles are vertebrates.

  • A. True

  • B. False

_____ cells are responsible for the formation of osteoblasts.

  • A. Osteocytes
  • B. Chondrocytes
  • C. Chondroblasts
  • D. Osteoclasts
  • E. Osteoprogenitor cells
  • F. Osteoblastic

_____ is a bone that constitute the axial skeleton.

  • A. Clavicle
  • B. Scapula
  • C. Patella
  • D. Radius
  • E. Sternum
  • F. Femur

Which of the following is false concerning cartilages and bones?

  • A. Cartilage does not have a direct blood supply while bones have direct blood supply
  • B. The process of ossification replaces a cartilage to bone
  • C. The protein that makes up cartilage is called chondrin while that that makes up bone is called ossein
  • D. Cartilage grows from both ends while bones grow from one of its epiphysis
  • E. They both have living cells within them
  • F. Haversian system is absent in cartilage but present in bones

What are Reptiles?

Reptiles are vertebrates (animals with backbone) belonging to the class reptilia. In Latin, the word 'reptile' means creeping animals.

Reptiles are believed to have evolved from another set of vertebrates called reptiliomorph, more than 300 million years ago. These were initially aquatic animals (lived in water) which became adapted to land.

Please read on the basic characteristics of life here.

It is noteworthy to state that reptiles are not amphibians, although they are generally believed to have evolved from amphibians. Meanwhile, some reptiles hibernate while others brumate.

During hibernation, an organism stays in a sleep-like state without food for a long period of time. During this period, the hibernating organism survives from the fat reserve under its skin.

Brumation on the other hand is quite similar to hibernation except that the animals are neither asleep nor live off their fat reserve. Instead, the organism's metabolic processes become very reduced thus resulting into the sluggishness (and reduced physical activities) of the brumating animal.

Please read on the characteristics of protists here.


Characteristics of Reptiles

Below are some of the characteristics or features of reptiles.

  • All reptiles are vertebrates

An animal is considered to be a vertebrate if it has a backbone or vertebral column. Reptiles, pisces (fishes), amphibians (toads and frogs), aves (birds) and mammals are all vertebrates.

Reptile's Backbone - Len Academy

Frilled lizard's skeleton

The backbone of reptiles commences from the lower end of their skull and runs throughout their body length. Present inside the backbone is the spinal cord which constitutes a part of the central nervous system.

Please read on skeleton and skeletal materials here.

You can read on the bones of the human body here.


  • They are cold blooded animals

Reptiles cannot physiologically regulate their body temperature. To explain this, let's briefly consider humans who have got a defined body temperature of 36.5oC.

This stability in human temperature is made possible via a process termed homeostasis, regardless the weather condition they may find themselves (whether in cold or warm conditions).

In the case of reptiles, the weather condition determines their body temperature. When it’s warm, their temperature increases and when cold, it decreases.

When the weather becomes too hot, they tend to move into places with shades of trees (or even water) in an attempt to lower their body temperature. We can therefore conclude that their body temperature is dependent on their environment.

Cold blooded animals are also referred to as poikilotherms or poikilothermic animals or ectotherms or ectothermic animals. This is so because their external environment aids in regulating their temperature.

Note: Humans are homeothermic animals (homeotherms or endotherms) since their temperature is regulated internally via various homeostatic organs.

Please read more on homeostasis here.

Although enzymes in humans work best at a specific temperature (36.5o), that isn’t the case in reptiles. Because they (reptiles) are ectotherms, their metabolic enzymes work efficiently over a wide range of temperatures.


  • Their bodies are covered in scales or scutes

Unlike mammals whose bodies are covered in hair/fur or birds whose bodies are covered in feathers (and their legs scale), all reptiles have their bodies covered in scales or scutes. The scales and scutes protect them from environmental dangers.

The chelonians (turtles and tortoises) in addition to having scales and scutes also possesses a hard protective shell called carapases. This gives them an extra protection to their upper bodies.

Snake's Scale - Len Academy

Snake's scale

Scales are generally composed of keratin and can either be tubular or ossified in appearance. In addition to providing protection and movement, they also prevent loss of water from the animal's body to their external environment; and this is one reason why some reptiles are capable of surviving in deserts.

Crocodile Scute - Len Academy

Crocodile's scute

The scutes are different from scales because they give more protection; and appear more like a dermal armor. They are found in tortoises, turtles and crocodiles.

Please read on amazing facts in biology here.


  • They are mostly oviparous while some may be ovoviviparous or viviparous

Most reptiles are oviparous animals. This implies that they lay eggs which are covered in shells. However, a few are ovoviviparous (that is, the eggs remain in the mother’s womb until they are ready to hatch) while others are viviparous, meaning that the young ones are born alive.

Some reptiles will incubate their eggs either by lying on them or by burying them below the earth until they hatch.

Finally, few reptiles will look after their young ones but only for a short period of time.


  • They undergo moulting or ecdysis

Moulting, also called ecdysis is a process whereby animals shed their skin. This moulting process is apparent in insects and reptiles. They remove the uppermost layer of their skin each time it gets worn out.

Parasites on the skins of reptiles are removed through the process of moulting.

Lizard shed their skins in patches while crocodiles shed the individual scales.


Other characteristics of reptiles include:

  • They respirate via their lungs.
  • They have three chambered heart.
  • Most are tetrapods (have four legs). Snakes are exceptions.

    You can read on the uniqueness of man here.

  • Most are carnivores with the exception of turtles and tortoises which feed on plant.
  • They are not hermaphrodites, hence their sexes are separate (male and females).

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An artery is composed of three layers:

  • The outermost layer is termed tunica adventitia (or tunica external). It consist mainly of collagen fibres and connective tissues that anchors the arteries to other nearby tissues.

  • The middle layer is named tunica media. It is made up of smooth muscles and elastic fibres that supports the artery in conveying blood at high pressures.

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All living organisms possess various features in order to survive in their environment. This is the concept of adaptation. As an instance, a fish is able to live in water because it has gills and fins.

Also, a camel is able to survive in the desert because it has large feet to aid walking on sand without sinking. It also has long eyelashes to help protect it from the blowing sand and wind.

Plants are also able to live in different habitats because they have the required adaptive features towards that habitat. For instance:

  • Plants that live in/on water are termed hydrophytes.

  • Plants that live on land with moderate amount of water are termed mesophytes.

  • Plants that live on deserts or arid lands are termed xerophytes.

The point is:

All organisms have various features on them that enables them adapt in their habitat

For a thing to be considered living, it must possess all the basic characteristics of life. These include:

  1. Movement

  2. Respiration

  3. Nutrition

  4. Irritability or Sensitivity

  5. Growth

  6. Excretion

  7. Reproduction

  8. Death

  9. Adaptation

  10. Competition

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This is the concept of anaerobic respiration

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A food chain is a diagram that shows the relationship between plants and animals within a habitat on the basis of how they rely on each other for food.

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  • Terrestrial (Land)
  • Aquatic (Water)
  • Arboreal (Treetops)

You can read on food chain here