Rabbit (Oryctolagus cuniculus)
Taxonomic position:
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Phylum: Chordata
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Sub-phylum: Vertebrata
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Class: Mammalia
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Order: Lagomorpha
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Genus: Oryctolagus
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Species: cuniculus
Habit and habitat:
Rabbit is a gentle and timid mammal. It shows hopping and leaping movements and lives in burrows. It is cosmopolitan in distribution. Rabbit is a herbivore and feeds on grass and vegetables. It lives in groups and is gregarious.
External morphology:
The body is elongated and cylindrical. An adult rabbit measures about 45 cm in length and weighs about 2.25 kg. The body is covered with fur, which helps in thermoregulation.
Body division:
The body is divided into head, neck, trunk and tail. The head bears mouth, nostrils, eyes, pinnae and vibrissae. Vibrissae act as tactile organs. The trunk is divided into thorax and abdomen. Two pairs of limbs are present. Hind limbs are longer and adapted for jumping. The tail is short and helps in danger signaling.
External features of rabbit
Coelom:
Rabbit is a coelomate animal. The body cavity is divided into thoracic and abdominal cavities by a muscular diaphragm, which plays an important role in respiration.
Digestive system:
The digestive system includes mouth, stomach, intestine and anus. A large caecum is present and contains cellulose-digesting bacteria.
The rabbit digestive system
Dentition:
Rabbit shows diphyodont and heterodont dentition. Canines are absent. A wide diastema is present between incisors and premolars.
The dental formula is I 2/1, C 0/0, PM 3/2, M 3/3.
Rabbit teeth
Respiratory system:
Respiration occurs through a pair of lungs. Air passes through nostrils, trachea, bronchi and alveoli. Gaseous exchange takes place in the alveoli.
Circulatory system:
The heart is four-chambered, with two auricles and two ventricles. The right side carries deoxygenated blood, while the left side carries oxygenated blood.Nervous system
The nervous system consists of the brain and spinal cord. The brain is divided into forebrain, midbrain and hindbrain.
Cardiac valves of mammals
Urinogenital system:
The kidneys excrete nitrogenous wastes in the form of urea. Rabbits show sexual dimorphism with separate male and female reproductive systems.
Reproductive system of rabbit