Morphology Of Rat

Rats are common model organisms in biology. They help in the study of anatomy, physiology, and genetics. Their body features are similar to humans. Studying their morphology teaches students about vertebrate body plans. It also supports topics like comparative anatomy and classification.

Let’s look at the key features of a typical lab rat (Rattus norvegicus).

General Body Structure

Rats have a bilaterally symmetrical, cylindrical body with clear segmentation. The entire body is divided into:

Head

Triangular and mobile
Contains eyes, ears, mouth, and nose
Eyes: Pink in albino rats, with a nictitating membrane (a transparent third eyelid)
Ears: Large, thin, and movable
Vibrissae (whiskers): Act as touch receptors
Nostrils (Nares): Located at the snout for detecting scents

Neck

Short, muscular, and flexible
Connects the head and trunk

Trunk

Divided into the thorax (front) and abdomen (rear)
The thorax bears two forelimbs; the abdomen bears hindlimbs
Mammary glands are present in females

Tail

Long, cylindrical, scaly, and hairless
Functions in balance, communication, and thermoregulation (regulating body heat)

Limbs and Movement

Rats are tetrapods (have four limbs):

Forelimbs: Shorter, used for grooming and handling food
Hindlimbs: Longer and more muscular, support running and jumping
Each limb ends in five digits with claws for digging and gripping

Skin and Body Covering

The body of a rat is covered with fine hair (fur). Its skin contains:

Sweat glands: Aid in cooling
Sebaceous glands: Secrete oil for waterproofing fur
Mammary glands: More prominent in females

Dentition: Gnawing Specialists

One of the most distinguishing features of rats is their specialised dentition for gnawing.

Incisors: One pair in each jaw, chisel-shaped, and grow continuously
No canines, creating a diastema (a toothless gap)
Molars: Present at the back for grinding
This dentition is called gnawing dentition, enabling them to chew wood, food, and even wires

Box to Remember: Scientific Classification of Rat

Taxonomic Rank	Classification
Kingdom	Animalia
Phylum	Chordata
Class	Mammalia
Order	Rodentia
Family	Muridae
Genus	Rattus
Species	Rattus norvegicus

Other Mammalian Traits

Viviparous: Gives birth to live young
Endothermic: Warm-blooded
Presence of a diaphragm: Assists in breathing
Brain and spinal cord: Well-developed, showing advanced nervous coordination

Important Notes:

Rats use their tail to balance and control body temperature
Vibrissae (whiskers) serve as tactile organs
Eyesight is poor in dim light, but their sense of smell and touch is highly developed
Female rats have 6 pairs of mammary glands

Summing Up

Studying rat morphology shows the basic structure of mammals. Its body plan, teeth, and senses explain key anatomy concepts. Rats are also used in medical, genetic, and drug research. They are similar to humans, reproduce quickly, and are easy to handle.

In short, learning rat morphology gives a strong base for higher studies and real-life science.

FAQs

Q1. Why do rat teeth grow continuously?

Rats are rodents, and their incisors do not have roots. Continuous growth ensures they stay sharp, but it also means rats must gnaw regularly to keep their teeth from overgrowing.

Q2. How many mammary glands does a female rat have?

Female rats usually have 6 pairs of mammary glands (12 in total) running along the thoracic and abdominal regions.

Q3. Can rats see in the dark?

Rats have decent low-light vision but rely more on whiskers and smell to navigate in the dark.