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Rodents biology and classification
Dr/ Walaa Samir Ahmed Nasser
Rodents research department
Research institute of medical entomology
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Superorder: Euarchontoglires
Order: Rodentia
Suborders
SciuromorphaCastorimorphaMyomorphaAnomaluromorphaHystricomorpha
Introduction
The mammals of Rodentia are called rodents’
They are found in vast numbers on all continents other than Antarctica.
Common rodents are
Mice
rats
Squirrels
Porcupines
and guinea pigs, etc.
feeding behavior
Rodents use their sharp incisors to cut wood, and bite predators.
Most rodents eat seeds or plants, cutting wood, Nearly all rodents feed on plants, seeds in particular, but a number of species eat insects .
Range of orders
Rodents make up the largest order of mammals. With about 2,277 species ofrodents,
over 40% of mammalian species belong to the order.
Their success is probably due to their small size, short breeding cycle, and ability tocut and eat a wide variety of foods.
Rodents are found in vast numbers on all continents except Antarctica, mostislands, and in all habitats except oceans. They are the only placental order.
All rodents have a single pair of upper and a single pair of lower incisors whichgrows constantly , followed by a gap , and then one or more molars or premolars,
Their anterior and lateral surfaces are covered with enamel, but the posteriorsurface is exposed dentine. Rodents lack canines, and have a gap between theirincisors and premolars.
dormouse
* What do they eat?Fruits, berries, flowers,
nuts and insects.
* Main characteristic:
Hibernation
porcupine
Characteristics:- Herbivorous
- Sharp spines over its body
- 60 to 90 cm
2 groups:
- New world porcupines
- Old world porcupines
Prairie dog
Characteristics:
- Herbivorous
- 30 to 40 cm
- Diet:
Insects, roots, seeds, fruits and
buds
Guinea pig
Characteristics:
• Cavies, cobayo, cobaya, acure, curí, cuilo cuis
• 22 cm
• South America
• Diet:
• Grass,(alfalfa) and some
leaves
Commensal rodents
The three commensal rodents include:
the Brown or Norway rat ( Rattus norvegicus )
the Black or Roof rat ( Rattus rattus )
the House mouse ( Mus musculus )
Classificationالتصنيف
The Brown or Norway rat الفأر البنى أو النيرويجى
The Black or Roof rat الفأر االسود أو المتسلق
The House mouse الفأر المنزلى
Common name Brown rat Black rat House mouse
Scientific name Rattus norvegicus Rattus rattus Mus musculus
Sexual maturity Attained in 2-3
months
2-3 months 1.5 months
Gestation period Averages 23 days Averages 22 days Averages 19 days
No. of young Averages 6-12 per
litter
Averages 6-8 per Averages 5-6 per litter
No. of litters Averages 4-7 per Averages 4-6 per year As many as 8 per year
Weight 250-500 grams 225 grams 15-25 grams
Common name Brown rat Black rat House mouse
Total length (nose to tip of tail)
45 cm
(nose to tip of tail) 35-45
cm
(nose to tip of tail) 15-
19 cm
Head and body Blunt muzzle, heavy
thick body
Pointed muzzle, slender
body, 16-20 cm
Small, 6-9 cm
Tail Shorter than head
plus body
Longer than head plus
body,
Equal to or a little
longer than head plus
body,
Ears Small large large for size of animal
Fur Coarse, generally
brown to gray-brown
Black to slate grey; tawny
above, gray-white below;
or tawny above, white to
lemon belly
Silky, dusky gray
Brown rats are natural burrowers and will burrow near their food and water supply in areas that provide harborage, such as vegetation and piles of clutter.
Black rats are excellent climbers and will nest in higher places rather than burrowing; hence requiring warmer climates than Brown rats.
House mice are ubiquitous and exist in all climates and are routinely found both indoors and out. Their constant gnawing, urinating, and defecating causes extensive damage
Rodents are nearly blind, using their sense of touch for guidance. Their long hairs, or "guard" hairs, are used for guidance as they move along walls and other objects.
Rodents have sensory pads on their feet which are very sensitive.
Rodents are excellent swimmers. Brown rats can swim in a 30 mph current without drowning.