FELASA Module 3 Basic Biology and Behaviour

FELASA Module 3: Basic Biology
 Animals are arranged into: Kingdom, Phylum, Class, Order, Family, Genus and Species
(Kind parrots can only fly going south)
 Rodents are part of the rodentia order
 Mice are from the Muridae family
 The two most common species are mus musculus (house mouse) and rattus
norvegicus (brown rat)
 Mongolian gerbil (meriones unguiculatus) is also part of the Muridae family
 The cricetidae family contains Chinese hamsters (cricetulus griseus) and Syrian golden
hamsters (mesocricetus auratus)
 The Caviidae family contains guinea pigs (cavia porcellus)
 Directions in anatomy
 Cranial in anatomy relates to directions towards the head and caudal refers to
directions towards the tail
 To the sides is lateral and to the centre is proximal
 Towards the back is dorsal and towards the stomach is ventral
 Most rodents have fur which is determined by multi-loci genes which leads to many
different coat colours
 Each loci can have alleles for multiple colours
 Long Evans rat
 Non-agouti- hairs are white at the bottom and pigmented on the tip
 Has black fur so is not albino and has full pigmentations
 Hooded means it only has coloured hair on its head and thorax
 In nature most rodents have a phenotype from a fully dominant genotype
 i.e they will be full agouti all over the body with variation in coat colour on the back and
belly
 May have a lighter appearance due to agouti triple hair colouring
 Muridae have long tails which are naked in mice and rats
 Gerbils have hairy tails
 Under the skin there are two lateral and one dorsal vein and to the ventral side there is
an artery




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 Muridae ears are naked
 Rodents use whiskers to touch their environment and rely on them to recognize food,
objects and other animals
 Vision doesn’t help orientation in rodents like it does in humans
 The nose and smelling sense is used for identifying other animals, finding food and
being stimulated by pheromones
 Teeth
 Mice and other rodents have 18 teeth
 4 incisors, 2 premolars, 12 molars
 They have no canines
 The have 2 dorsal and 2 ventral incisors which grow continuously
 The Danish name for rodents is gnavere (gnawers) from these teeth
 If rodents do not have something to gnaw on these teeth overgrow
 Salivary glands
 Submandibular glands are the largest glands in rodents
 This is different to humans which have the parotid glands as the largest

,  Larynx
 Respiratory air from the nose and mouth passes in and out of the larynx
 The larynx fixes the trachea to the caudal part of the mouth
 On the outer surface of the laryngo-tracheal surface we find the thyroidea and
parathyroideal glands
 These secrete endocrine hormones of importance for metabolism and calcium
regulation




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 Food passes from the mouth through the thorax via the eosophagus
 The esophagus runs along the thorax with the trachea
 The left lung has one lobe and the right lung has four lobes
 The lungs oxygenate blood and end it to the heart
 The thymus is located in the cranial opening of the thorax
 The thymus is the body’s T-cell generator
 It is large in young rodents but decreases in size with age
 The entire thorax and all its organs are covered by a membrane called the pleura




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 Arteries
 Blood flows through arteries from the heart to capillaries in the most distant parts of
the body
 The aorta is the largest artery and follows a dorsal path through the thorax and
abdomen
 Caudally the aorta divides into the ischiadic arteries to bring blood to the legs
 Blood flows cranially through a brachiocephalic trunk to the fore-legs and to the
head through the carotid arteries




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 Veins
 When leaving the capillaries blood flows back through the veins