External Features of Mammalia

Introduction to Experiment

Class Mammalia is the most dominant group of animals found in almost all types of habitats. The presence of mammary glands, external hairs and pinnae are distinctive features of this class. In this simulation, the characters of class Mammalia are investigated with reference to a preserved specimen- Oryctolagus Lagomorpha.

Experiment Procedure

A mammalian preserved specimen- Oryctolagus Lagomorpha, commonly called rabbit, is observed under the naked eye. The specimen’s external characteristics are studied, and a neat labelled diagram is drawn based on the observations.

The external characteristics that are studied in this simulation are given below:

• Oryctolagus Lagomorpha is a short-tailed rabbit, which is a long-eared burrowing mammal commonly found in thick vegetation.
• The body of a rabbit is divided into the head, neck, trunk, and a small tail. It is covered with hair and measures up to 40 cm in adults. The presence of hair is a distinct feature of mammalia.
• The external features of the rabbit include a large head, a pear-shaped nose, a blunt mouth, two movable lips, vibrissae, external ears, a short, flexible neck, and a large cylindrical trunk.
• At the anterior end, the hindlimbs are present, which are longer and more powerful than the posterior forelimbs. The limbs are equipped with four claws.
• Sexual dimorphism is observed in rabbits. The male rabbit features a penis that helps in copulation and also possesses scrotal sacs in which a pair of testes are lodged.
• Unlike males, females are bossier and more aggressive and possess well-developed mammary glands, nipples, and a vulva, a reproductive opening located below the anus and helps in copulation. The presence of mammary glands is a characteristic feature of the Mammalia class.
• In both sexes, the anus is located at the posterior end of the abdomen near the tail, where faeces is expelled.
• As the rabbit is a mammal, it is warm-blooded, viviparous and feeds on short grasses.

Based on the characters, the taxonomical classification of the rabbit specimen is also studied in this simulation.

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