ANIMAL REPODUCTION

1. GORILLA ANIMAL REPODUCTION by: Te-Ina 11C

2. ...Types of Gorillas... Western Lowland Gorillas (gorilla,gorilla,gorilla) -wide spread species -lives low land rainforests -short height/light weight -reddish/ grey hair/shoulders/head -Broad face/skull -shorter hair -most common gorilla in the zoo Eastern Lowland Gorillas -Small population -Shorter hair -Live only in Zaire -Rarely seen in zoos -Tallest/Heaviest -Black/Grey coloured hair -Long/narrow face/skull Gorillas are the largest and among the most sexually dimorphic of all extant primates. Mountain Gorilla (gorilla, gorilla, beringei) -small population -Large heavy -Hair thick/glossy/bland/long -Gorilla studied the most -None in Zoos

3. Sexual Dimorphism Sexual Dimorphism Finally, lowland and mountain gorilla females do not differ significantly in adult body size, but mountain gorilla males are significantly larger than lowland gorilla males, suggesting mountain gorillas are characterized by a higher degree of sexual dimorphism in body size. Male gorillas are much larger than the females, and are almost twice as heavy. Adult male gorillas are called silverbacks because they have a saddle-shaped patch of silver hair on their backs after they are about 12 years of age. Gorillas have been involved in broad-level comparisons among large-bodied hominoids or in studies of the African apes, comparisons between gorilla subspecies have been rare. During the past decade, however, behavioral, morphological, and molecular data from a number of studies have indicated that the western lowland (Gorilla gorilla gorilla) Gorillas are the largest and among the most sexually dimorphic of all extant primates. While gorillas have been involved in broad-level comparisons among large-bodied hominoids or in studies of the African apes, comparisons between gorilla subspecies have been rare. During the past decade, however, behavioral, morphological, and molecular data from a number of studies have indicated that the western lowland (Gorilla gorilla gorilla) and eastern mountain (Gorilla gorilla beringei) subspecies differ to a greater extent than has been previously believed. In this study I compare patterns of relative growth of the postcranial skeleton to evaluate whether differences between subspecies result from the differential extension of common patterns of relative growth. In addition, patterns of ontogeny and sexual dimorphism are also examined. Linear skeletal dimensions and skeletal weight were obtained for ontogenetic series of male and female G. gorilla (n = 315) and beringei (n = 38). The difference differences in patterns of relative growth, ontogeny, and sexual dimorphism between sexes of each subspecies and in same-sex comparisons between subspecies. Results indicate males and females of both subspecies are ontogenetically scaled for postcranial proportions and that females undergo an earlier skeletal growth spurt compared to males. However, it shows that the onset of the female growth spurt occurs at different dental stages in lowland and mountain gorillas and that mountain gorillas may be characterized by higher rates of growth. Finally, data demonstrate lowland and mountain gorilla females do not differ significantly in adult body size, but mountain gorilla males are significantly larger than lowland gorilla males, suggesting mountain gorillas are characterized by a higher degree of sexual dimorphism in body size. Male gorillas are much larger than the females, and are almost twice as heavy. Adult male gorillas are called silverbacks because they have a saddle-shaped patch of silver hair on their backs after they are about 12 years of age. Eastern mountain (Gorilla gorilla beringei) subspecies differ to a greater extent than has been previously believed. In this study I compare patterns of relative growth of the postcranial skeleton to evaluate whether differences between subspecies result from the differential extension of common patterns of relative growth. In addition, patterns of ontogeny and sexual dimorphism are also examined. Linear skeletal dimensions and skeletal weight were obtained for ontogenetic series of male and female G. gorilla (n = 315) and beringei (n = 38). The difference differences in patterns of relative growth, ontogeny, and sexual dimorphism between sexes of each subspecies and in same-sex comparisons between subspecies. Males and females of both subspecies are ontogenetically scaled for postcranial proportions and that females undergo an earlier skeletal growth spurt compared to males. However, the onset of the female growth spurt occurs at different dental stages in lowland and mountain gorillas and that mountain gorillas may be characterized by higher rates of growth.

4. Diagram of male and female sexual organs Compared to their body mass, gorilla testes and penises are small: Gorilla testes weigh 30-35 g, those of a chimpanzee about 120 g. As a rule, an erect gorilla penis is only 3 cm long, whereas a chimpanzee penis reaches about 8 cm. The female gorillas boobs will enlarge when she has had her child

5. Courtship --> Mating -->Fertilization Gorillas have no mating season. Mating and births occur throughout the year. Female gorillas have a hormone cycle (similar to humans), which is usually 26-32 days long. The female comes into heat in mid-cycle. This can last up to 4 days, but usually it lasts only one day. During this phase the female's behaviour and the relations with the other group members change. Mating in captivity She approaches an adult males (and occasionally females) to initiate mating, while other animals seek more contact with her. If the egg is not fertilised, the mucous membrane of the uterus is flushed out of the body with menstrual bleeding, just as in humans. Bleeding lasts for 2-3 days and is considerably weaker than in humans. Mating in the wild

6. Male or female? -->Parental Care There is no way of determining whether the child is going to be a male or a female. Female gorillas carefully nurture their young. Baby gorillas learn to crawl at about 2 months (much earlier than humans) and can walk before they are 9 months old (earlier than most humans). They can grasp their mother's fur to ride on the mother's back at 4 months. Baby gorillas are fed mother's milk for the first 2 1/2 years of life. When they are weaned, gorillas begin to build their own sleeping nests out of vegetation (and not use their mother's nest anymore). Young gorillas stay with their mother for 3-4 years. Adult male gorillas (silverbacks) will care for weaned orphaned young gorillas. Mother feeds her child/other female watches Mother feeding her infant

7. Gorillas Life Cycle At birth, infants weigh 4-5 pounds (1.8-2.3 kg) and have sparse hair covering their pink-gray skin. At about nine to 10 weeks, they begin to crawl on their own and soon walk on all four limbs. A white patch of hair appears on the rump of gorilla infants at about the same time they begin to walk. The white patch helps the mother keep track of the infant and assists other group members in identifying the gorilla as an infant. The rump patch begins to disappear at about age 3, the same age that weaning usually begins. Females remain with their natal group until about age 8 or 9, then join an unrelated group or a solitary male. Males remain with their natal group until about age 12, then begin to go off on their own. Solitary males try to attract females from other groups to form their own group.

8. Did you know... • When a gorilla drinks, which is rarely, it soaks the back of its hand and sucks the water from the fur. • As he matures, a male gorilla's skull develops a bony ridge which makes his head dome-shaped.. • Social grooming can relax a gorilla to the point that it will go into a trance ...MoRe InfOrMatiOn….. …..What they eat….. Most of the foods gorillas eat are found year-round in the Hagenia forests so that is where they spend most of their time. It is their primary habitat. Bamboo shoots are available only a few months of the year, usually, but not always, between August and December. The gorillas visit the bamboo forests only when fresh shoots are available. Since the growth of bamboo shoots is highly variable from year to year, depending on weather, the bamboo forest is a secondary habitat for the gorillas. The gorillas also eat the soft centres of the giant Senecio trees, so occasionally they make the long hike up the mountain sides to the subalpine zone where these plants live.

9. ...Gallery... I’m so Lonely Male gorilla Location Location Location Young Gorilla Lost dude Just hanging around You know you want me…. How YOU doing??

10. Bibliography -->References Books: Life is a band (Gorillas) By: Richard & Louise Spinbarg Gorilla By: Dougal Dixon Gorilla By: Redmond Gorilla By:Patricia Kendell Research Websites. www.google.com keywords Gorilla *Life cycle *Parental Care *Sexual Dimorphism *Behaviour *Courtship *Mating *Fertilization Other websites http://pin.primate.wisc.edu/factsheets/entry/gorilla/links student.britannica.com/comptons/art-17425/Adu... http://www.wildkingdom.tv/video/14464-gorilla-mating-in-the-wild.html www.berggorilla.org/.../texte/30typus.html www.dkimages.com/discover/Home/Animals/Mammal... www.cosmosmagazine.com/node/618 homepage.mac.com/.../images/Knight/page1.htm www.awf.org/content/headline/detail/3909 www.whrc.org/africa/prioritypops/maps_data.htm www.safariweb.com/uganda/safaris.htm www.panda.org/.../current_top_10/gorilla.cfm