15
Feb
The gestation period ranges between 21 and 29 days and young rats are able to reproduce within 3 to 5 months of their birth. Females are polyestrous and ovulate spontaneously.
An average female is capable of giving birth approximately seven times per year.
Rat reproduction description. Breeding and reproduction in rats can decrease because of factors such as age malnutrition abnormal light cycles cold environment cysts on the ovaries tumors and inadequate nesting material. Pregnant females may abort abandon or eat their babies because of inadequate food lack of water overcrowding in group housing inadequate nesting materials sick or deformed. The size of the testes in relation to the rats body weight will vary between individuals.
However within mammals the size increases when the mating habits are more polygamous than monogamous. With rats the testes are larger due to their polygamous mating habits. The onset of puberty in the female rat results from a cascade of events following establishment of a pulsatile luteinizing hormone LH release after the fourth postnatal week approximately thirty days of age that leads to ovarian maturation Andrews and Ojeda 1981.
Before this time the reproductive tract is inactive. The reproductive system also supplies nourishment for the offspring after birth and produces female sex hormones. The main system structures of the female rat are the vagina ovaries uterus and mammary glands.
The vagina is the short muscular canal that leads from the female rats uterus to the outside of the body. True rats are omnivorous capable of eating a wide range of plant and animal foods and have a very high birth rate. When introduced to a new area they quickly reproduce to take advantage of the new food supply.
Females are polyestrous and ovulate spontaneously. Breeding is largely determined by food availability. Litter size normally 6 - 11 gestation is 21-24 days young weaned at about 28 days.
Females can be sexually active. The major reproductive organs of the male rat are the testes singular. Testis which are located in the scrotal sac.
Cut through the sac carefully to reveal the testis. Rat pups are born 45-6 g affected by litter size eyes will open at 14-17 days and ears at 25-35 days. They are hairless fully haired 7-10 days and with no erupted.
The female reproductive organs of rat are uterine horns below kidney oviduct tiny tube that connects uterine horn to ovary and ovary. Taxonomically rat and mouse are not different species. The former differs from the latter by its larger size.
The brown rat Rattus norvegicus also known as the common rat street rat sewer rat wharf rat Hanover rat Norway rat Norwegian rat and Parisian rat is a widespread species of common ratOne of the largest muroids it is a brown or grey rodent with a head and body length of up to 28 cm 11 in long and a tail slightly shorter than that. It weighs between 140 and 500 g 5 and 17. The peak breeding seasons are summer and autumn.
Females can produce up to 5 litters in one year. The gestation period ranges between 21 and 29 days and young rats are able to reproduce within 3 to 5 months of their birth. Neonates are altricial like most rodents and their eyes do not open until 15 days of age.
Reproduction Rats have two distinct cervices and uterine bodies. There are separate urethral and vaginal openings. There is a vaginal closure membrane which is lost at puberty.
The inguinal canal remains patent throughout life. Rats have an os penis or os clitoridis associated with external genitalia. Rat reproduction has been most intensively studied in the brown rat.
This prolific rodent reaches sexual maturity at three months and may produce up to 12 litters of 2 to 22 young 8 or 9 is usual per year with peaks in the spring and autumn and a gestation period of 21 to 26 days. Rats are clever quick thinkers. Successful but content with living a quiet and peaceful life.
In Chinese culture rats were seen as a sign of wealth and surplus. Because of their reproduction rate married couples also prayed to them for children. Paired with the Celestial Stems 天干 Tiān gān there is a 60-year calendrical cycle.
Rattus is a placental mammal with dependent young. Litter size averages 3-65 individuals Tobin et al 1994 yet in laboratory trials the litter size ranges from three to 10 and averages 5-8 Innes 2005 with frequency of litters dependent on season and food supply. The interval between litters may be as little as 27 days.
Rats brush the long hairs against objects or the floor helping them build up a detailed picture of their environment. 6 With eyes on either side of their head that can move in opposite directions rats are even able to see whats happening above them. An average female is capable of giving birth approximately seven times per year.
Around 18 hours after giving birth females experience postpartum estrus and mate again. This reproductive function is responsible for the huge birthrates of Norway rats which can reach 60 young each year per female. General Biology and Reproduction of Kangaroo Rats.
Kangaroo rats conduct breeding from February to October in southern desert states. The breeding period is somewhat shorter in the northern states. The gestation period is estimated at 30 days.
Reproductive rates differ as per species food accessibility and density of rodent populations. Female urogenital structures Urethral orifice- is the opening into the urethra part of the urinary system. Vaginal orifice- is the opening into the vagina part of the reproductive system.
Male urogenital structures Penis - is hidden on the male rat beneath a. They are about 9 to 11 inches long without the tail. Male rats are usually larger than females.
Pet rats are available in several colors and coat patterns because of specialized breeding. The common color variations include brown black tan gray and white with both lighter and darker shades as well. Some of the more exotic colors are.
Part of the rat problem is their incredible fecundity. Rats begin breeding as soon as five weeks of age and continue until about age two. Females are fertile approximately every three weeks and during this time they have been known to mate up to 500 times in six hours.