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Fauna of Islands of the Indian Ocean
JOrnitho: Starting a new topic because this doesn't fit the already existing ones about islands (Atlantic and Pacific). I saw in the map of the Neocene that Adaman and Nicobar still exist, so I thought about some species that could exist here. Since it was a chain of islands, I think that the fauna could be different in each of them. For example, the largest one (Adaman itself) could have maintained large introduced species such as the chital deer and feral dogs. These animals would have descendants in the Neocene. Meanwhile in Great Nicobar, terrestrial predators could be absent and the largest animal could be a flightless descendant of the Nicobar pigeon . What do you think?
Àâòîð: JOrnitho ïèøåò: large introduced species We can certainly say, their descendants will be dwarf. JOrnitho ïèøåò: a flightless descendant of the Nicobar pigeon This species is classified now as near threatened. So, it is more probable that a descendant of any continental species will do it... in conditions of absence of rats and mice.
Áèîëîã: JOrnitho Another topic - our English part of the forum keeps expanding! Thanks! a flightless descendant of the Nicobar pigeon Would be great, but the Author mentioned above that it would hardly survive because of being already threatened in holocene. So, we have to use another ancestor. Which can also become colorful, not necessarily dull grey. Or even crested, like crowned pigeons.
JOrnitho: In this case, I think that the ancestor of a flightless bird in Nicobar could be the domestic chicken left behind by the men. Being already terrestrial, it could have grow to a large size.
Áèîëîã: JOrnitho Nice idea! Like the megapode, but flightless.
JOrnitho: Áèîëîã ïèøåò: Nice idea! Like the megapode, but flightless. Yes! Perhaps even like the extinct Sylviornis with the exception that they will incubate their eggs. These birds could have strong legs to use in intraspecific fights. Meanwhile in Andaman Island, there would be a dwarf descendant of the chital deer being hunted by the top predator of the place, a canid.
Áèîëîã: JOrnitho Sylviornis Wow, you've introduced me to an extinct species I never knew about before! Good idea. in Andaman Island, there would be a dwarf descendant of the chital deer being hunted by the top predator of the place, a canid Chital deer was introduced on Andaman in the XX century, as can be found in Internet. A descendant there is a good idea! Chital deer is beautiful, so the descendant can inherit that.
JOrnitho: Áèîëîã ïèøåò: Wow, you introduced to an extinct species I never knew about before! Good idea. The Sylviornis is a very interesting animal. It shows how the evolution in islands can generate strange animals. Perhaps in the Neocene these islands could have animals with different and even bizarre forms.
Áèîëîã: JOrnitho OK, so be it!
JOrnitho: Finished the description of the giant descendant of the domestic chicken. I'll finish the one for the dwarf deer of Andaman later today. Emperor junglefowl (Gigantogallus imperator) Order: Galliformes Family: Phasianidae Habitat: Forests and woodlands of Nicobar Island During the Holocene, the man introduced many species to other continents. Some only because of their ornamental value, while others were introduced because they were useful for agriculture. Among the birds, the domestic chicken (Gallus domesticus) was the species that reached more continents. With the disappearance of humanity, they were left behind to fend for themselves. Some were successful in surviving and continued to evolve. In the Neocene, the chickens that were left in Nicobar Island had evolved into a large flightless species, the Emperor junglefowl. Such characteristic was only possible due to the disappearance of terrestrial predators in the island. The emperor junglefowl is the largest animal of Nicobar Island. A completely adult male can reach 175 cm of height, surpassing their relative of the Genus Aepygallus from Mauritius. The female has a more modest size, 147 cm. These birds are also heavy, with the male having 32 kg while the female has 23 kg. To sustain such weight, their bones had evolved to be denser, like that of an ostrich. They have a large skull with a high and laterally compressed orange beak. Its yellow colored legs are rather short, but have strong toes with long nails. Most of their height comes from their long necks. The wings are reduced, making it impossible for them to fly. Beyond the size, the only other difference between the sexes is that the males have a bare face with red skin that forms a comb and wattles. These bare parts become bright during the nesting season. The comb is large, reaching 20 cm in older males. The wattles are long and come down from both sides of their head, below the auricular hole. This gives the bird the appearance of having earlobes. The female lacks such structures and the skin on their face is pale pink. Both sexes have the same dark brown plumage, with yellowish-brown underparts. The tails are short, being metallic green in the males and brown in the females. The emperor junglefowl is omnivorous. It'll feed on arthropods, terrestrial gastropods, seeds, fruits and leaves. They use their long legs to reach fruits and leaves in tree branches. These birds will also visit beaches in search of algae and shellfish, which is excavated out of the sand. Their shell is crushed by the birds' strong beak. This species lives in harens formed by a dominant male and two to four females. Their nesting season starts during the end of the dry season. The females will make nests in the territory of the group, usually hidden among bushes and below trees, near its roots. Usually three to six reddish-brown eggs are laid, which are incubated solely by the female for 30 days. The male will stay patrolling his territory in search of possible rivals and invasor, which will be expelled with kicks of their strong legs. After hatching, the chicks are already capable of leaving the nest. They will follow the mother back to the group and if other females already have chicks, a crèche is formed by them. The young reach full adult size in about six months. At this point, the male chicks are expelled by their father. The females can remain indefinitely, but they leave as soon as sexual maturity is reached with two years of age. At this point, they will leave, with some even traveling in small female-only groups in search of a male to form their own harem. The lifespan of this species is 15 years.
Áèîëîã: JOrnitho Great species!
JOrnitho: Áèîëîã ïèøåò: Great species! Thanks! I finished the description of the dwarf deer of Andaman Island. Dwarf chital (Nanoaxis maculatus) Order: Artiodactyla Family: Cervidae Habitat: Forests and woodlands of Andaman Island During the Holocene, humans had caused several impacts on the environment. Among their actions was the introduction of exotic species. The chital deer (Axis axis) was introduced by the humans in the Andaman Island, becoming a very successful species here. Such success allowed them to survive in the Neocene, with its descendant now living here. The dwarf chital is such a descendant. This small cervid is a common species across the forests and woodlands of the Island. The dwarf chital has 50 cm of shoulder height and 110 cm of length. The male has a pair of 15 cm long antlers that have only one short branch in its middle. The fur of both male and female in the upperparts are rufous and completely covered in white patches. The abdomen, rump, throat, insides of legs, ears, and most of the tail are all light brown. The tail, 20 cm long, has a dark tip. They feed on a wide variety of vegetation, including grasses, foliage, browse, fruit, and water plants, depending on the local habitat. This deer is active throughout the day. In the summer, time is spent resting under shade. As days grow cooler, foraging begins before sunrise and peaks by early morning. Activity slows down during midday, when the animals rest or loiter about slowly. Foraging recommences by late afternoon and continues till midnight. They fall asleep a few hours before sunrise, typically in the forest. When cautiously inspecting its vicinity, the dwarf chital stands motionless and listens with rapt attention, facing the potential danger, if any. This stance may be adopted by nearby individuals, as well. As an antipredator measure, the deer flee in groups, sprinting often and hiding in dense undergrowth. The running dwarf chital has its tail raised, exposing the black tip. A gregarious animal, the dwarf chital forms matriarchal herds comprising an adult female and her offspring of the previous and the present year. For most of the year, adult males and females are segregated into different herds. Female herds are larger while bulls form small groups and may even travel alone. Young bulls may associate with older bulls or close related female groups. Male and female herds come together only during the mating season, which starts during the middle of autumn. Herd membership is typically that of 15 to 30 individuals, aggregations of as many as 100 individuals can happen. A vocal animal, this deer gives out bellows and alarm barks. Bellowing coincides with rutting, which starts during the middle of the middle of the dry season. Dominant males guarding females in oestrus make high-pitched growls at less powerful males. Males may moan during aggressive displays or while resting. Dwarf chitals, mainly females and juveniles, bark persistently when alarmed or if they encounter a predator. Fawns in search of their mother often squeal. The chital can respond to the alarm calls of several animals The gestation period of the dwarf chital is of 6 months and they usually bear one offspring at a time, but sometimes produce twins. Females usually give birth in dense growth so that they are hidden from the rest of the herd and predators. Weaning is completed at around 7 months and at around 12 months the fawn is independent, the young males remain in its mother herd until reaching one year. After that, they will walk away from the herd, but can return to it occasionally. Adult males often fight between one another for the chance of mating of females, using kicks and bites more than their antlers. Reaching sexual maturity with 3 years, the dwarf chital have a lifespan of 17 years.
ìåäâåäü: Why do not they have white rump patches like their ancestors? It would be a more visible warning in forests.
Áèîëîã: ìåäâåäü The white patches can be a way of disguise in the foliage, not warning.
JOrnitho: ìåäâåäü ïèøåò: Why do not they have white rump patches like their ancestors? It would be a more visible warning in forests. The white patches are located in their upperparts, like their ancestors. They are larger than the spots of the chitals of the Holocene. I believe that for warning, the black tip in the tail would be better. The white patches are camouflage, like how Áèîëîã said.
Áèîëîã: JOrnitho Good deer!
JOrnitho: I finished the description of the predatory canid of the Andaman Island. Strong-jawed dog (Ferociocanis borophagus) Order: Carnivora Family: Canidae Habitat: Forests and woodlands of Andaman Island During the Holocene, humans had caused several impacts on the environment. Among their actions was the introduction of exotic species. Being a common companion, the dog was among the animals that were spread by the humans across several continents. With humanity’s disappearance, these mammals stayed behind. The survivors left several descendants during the Neocene. In the Andaman Island, the dog gave rise to the strong-jawed dog. The strong-jawed dog is the largest predator of the Island. However, if compared to continental predators, they are small. An adult has 40 cm of height at the shoulders and 89 cm of body length. Their fur is short, being dark brown in the upperparts and reddish-brown in the underparts. Their tail have short fur and have a white tip. This species has strong muscles in the skull and powerful teeth and jaws. Such characteristics allow them to crush bones. They are carnivores, feeding on any large vertebrate that inhabits Andaman Island. Their main prey is the dwarf chital. While the strong-jawed dogs have a small size, they compensate for it with their powerful bite that allows the canids to kill their prey more easily. They will occasionally visit beaches in search of marine animals that ended up there and died. Differently from wolves from the Holocene, this canid hunts in pairs and doesn't form packs. The strong-jawed dog is monogamous, with them being more common to be seen in pairs. They are sometimes accompanied by their most recent litter of pups. Scent marking through urination and defecation is common around strong-jawed dog den areas and on the trails they most often use. Scent marking is used to assist in territorial defense. The females have only one breeding cycle each year. They excavate dens, with the breeding pairs being spaced well apart and maintaining a core territory around their dens. Breeding occurs during the end of the dry season, with the mating period lasting up to 29 days. Gestation lasts 72 days, and the timing of the births coincides with the annual abundance of food, usually the beginning of the monsoon. The female gives birth to 3-5 pups. The pups are born with closed eyes that open after 13 days, with the ears erecting after 12 days. Their teeth erupt at 16 days after birth, and the eruption of adult dentition is completed after five months. Pups are born with soft fur that ranges in color from light gray to dark brown. At the age of one month, their fur is shed and replaced with one similar to that of an adult. Lactation lasts for up to 9 weeks and the pups begin to eat meat at the age of 19 days. After three weeks that the lactation is concluded, the parents expel the pups from their territory. Females reach sexual maturity after 11 months, while males at 22 months. They have a lifespan of 17 years.
Áèîëîã: JOrnitho Good dog!
JOrnitho: I was thinking about some other animals for the Andaman and Nicobar Islands. One would be a descendant of the wild pig similar to a elephant, but with the size of a tapir. Other idea would be a large bird if prey that hunt the giant junglefowl. It could also live in nearby areas of the continent. What other species do you think that could also live here? Maybe some of the continent that reached it after the humans disappeared?
Áèîëîã: JOrnitho a descendant of the wild pig similar to a elephant, but with the size of a tapir OK, normal. Although tapirs are not much larger than wild boars. Other idea would be a large bird if prey that hunt the giant junglefowl. Resembling the Haast eagle? Well, the islands seem too small for a so large predatory bird, but OK. What other species do you think that could also live here? Maybe some of the continent that reached it after the humans disappeared? Possible, but only for small birds, the size of a sparrow or finch. Although they could become larger after settling on the islands.
JOrnitho: Áèîëîã ïèøåò: Resembling the Haast eagle? Well, the islands seem too small for a so large predatory bird, but OK. I think that would be smaller, maybe with the size of harpy or golden eagle. It would kill the junglefowl by coliding against its neck with full force and using the claws Áèîëîã ïèøåò: Possible, but only for small birds, the size of a sparrow or finch. Although they could become larger after settling on the islands This is interesting. A finch could fill the niche of parrots and other species that don’t exist in the islands.
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