Отправлено: 06.08.22 20:05. Заголовок: Fauna of Islands of the Indian Ocean

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?

 Отправлено: 22.01.23 23:27. Заголовок: Биолог пишет: But d..

Биолог пишет:

цитата:

But do you expect the rats to eat the entire contents of coconuts? If this is a common action, the coconut palm would not survive for long, having limited numbers of nuts eaten by rats before they germinate into new trees.

What parts of the coconut you think that they could eat without destroying the chances of germination? Perhaps the fruits would only be a part of their diet?

 Отправлено: 23.01.23 14:19. Заголовок: JOrnitho I think th..

JOrnitho
I think the rats would eat something else. And in the cocnuts, they would eat only the soft parts around the seed. Also, given the hardness and toughness of the coconut shell, the rats would have to acquire adamantium-like incisors

 Отправлено: 23.01.23 19:02. Заголовок: Биолог пишет: Also,..

Биолог пишет:

цитата:

Also, given the hardness and toughness of the coconut shell, the rats would have to acquire adamantium-like incisors

Well, some species of rat really eat the coconuts, being considered plagues for the production of that fruit. What if the coconut of Andaman and Nicobar developed a strategy? Perhaps a thick, soft and sweet part around the true seed, which is sour and not palatable for the rodents?

 Отправлено: 23.01.23 22:58. Заголовок: JOrnitho some speci..

JOrnitho

цитата:

some species of rat really eat the coconuts, being considered plagues for the production of that fruit.

I did not know that, my fault.

цитата:

What if the coconut of Andaman and Nicobar developed a strategy? Perhaps a thick, soft and sweet part around the true seed, which is sour and not palatable for the rodents?

Wow, great! But the seeds would obviously require protection from sour juice as they germinate through it (in palms, the seeds do not fall out before germination). Another way is to develop a toxin, and another one is a sharp, repulsive smell (like durian has it, but not necessarily putrefactive) that would drive the rats off without harming the seeds inside.

 Отправлено: 24.01.23 04:03. Заголовок: Биолог пишет: Anoth..

Биолог пишет:

цитата:

Another way is to develop a toxin, and another one is a sharp, repulsive smell (like durian has it, but not necessarily putrefactive) that would drive the rats off without harming the seeds inside.

Perhaps the coconut could have its external portion being sweet and soft, but the seed itself have a terrible smell? The rats would this part, but leave the rest behind. By doing it they help the plant germinate.

 Отправлено: 24.01.23 11:38. Заголовок: JOrnitho Yes, why n..

JOrnitho
Yes, why not.

 Отправлено: 24.01.23 12:02. Заголовок: JOrnitho If you'..

JOrnitho
If you'll release this gliding rodents and interesting coconuts I'll back to making chapter about them, but it isn't 100% unformation.

 Отправлено: 28.01.23 15:09. Заголовок: I'll start to wo..

I'll start to work in the description for these rodents today, this week had been so busy. Someone could help me with the coconut? Botanic isn’t my area of expertise.

 Отправлено: 28.01.23 19:19. Заголовок: JOrnitho What kind ..

JOrnitho
What kind of help do you need?

 Отправлено: 29.01.23 12:18. Заголовок: Биолог пишет: What ..

Биолог пишет:

цитата:

What kind of help do you need?

To describe the soft layer that cover the seed and is consumed by the rats. I thought that it could have appeared as way to protect the fruit from the elements, but to germinate is necessary to be removed. Also, these coconuts would be smaller than their ancestors.

 Отправлено: 29.01.23 12:49. Заголовок: JOrnitho But the co..

JOrnitho
But the coconuts have a thick and tough shell that is a great protection from elements, isn't it? So this shell will become much thinner and/or softer. Also, note that the palm coconuts are adapted to floating from island to island across the ocean water, the seeds being protected from the salty water by the shell, and the soft tissue inside providing buoyancy. Will this stop in the case of your idea?

 Отправлено: 29.01.23 20:15. Заголовок: Биолог пишет: But t..

Биолог пишет:

цитата:

But the coconuts have a thick and tough shell that is a great protection from elements, isn't it? So this shell will become much thinner and/or softer. Also, note that the palm coconuts are adapted to floating from island to island across the ocean water, the seeds being protected from the salty water by the shell, and the soft tissue inside providing buoyancy. Will this stop in the case of your idea?

No, they would continue this way. How we could explain biologically the creation of this soft part of the shell? Perhaps a defense against predation? The rats would eat this part, but leaving the interior intact?

 Отправлено: 29.01.23 20:28. Заголовок: JOrnitho OK, so be ..

JOrnitho
Yes, OK, so be it.

 Отправлено: 01.02.23 04:20. Заголовок: Finished the first g..

Finished the first group of squirrels and the description of a bird of prey:

Andaman flying squirrel (Parapteromys versicolor)
Order: Rodentia
Family: Sciuridae
Habitat: Forests of Andaman Island, tree canopy
During their expansion, the humans had introduced several species. The northern palm squirrel (Funambulus pennantii) was left by them on the Andaman Islands, where they survived to the transition between the Holocene and Neocene. In a case of evolutionary convergence to other rodents, their descendants had developed large membranes (or patagia) that span the space between the fore- and hindlimbs, and additional membranes connect the trailing edges of the hindlimbs with the proximal parts of the tail. These insular flying squirrels form the tribe Parapteromyini, which is formed by two genus: Parapteromys and Microparapteromys. Through rafting, they had spread from Andaman to several nearby islands, including Nicobar.

The genus Parapteromys is formed by the giant insular flying squirrels. Its main representative is the andaman flying squirrel. This species is also the largest, with a head-to-body length of 38 cm and a tail of 34 cm. Their underparts are white, while the upperparts are rufous-brown, with a darker midback. The tail is black with a white tip. Their head is pale gray.

They are diurnal animals, with a diet composed mostly of seeds, nuts and fruits. However, they’ll also eat insects, eggs, chicks, smaller mammals and reptiles.

The Andaman flying squirrel is a solitary animal, spending a majority of its life without interaction with others of its own species, with the exception of during mating season and females with young. The gestation period is 34 days, with the breeding taking place in grass nests during the autumn. Litters of two or three are common. The young are weaned after about 10 weeks and are sexually mature at 9 months. This species has a lifespan of 7 years.

Another representative of the genus is the Nicobar flying squirrel (Parapteromys nicobariensis), which is endemic to Great and Little Nicobar. This species is the smallest representative of the genus, with 32 cm of body length and a tail of 24 cm. Their underparts are yellowish-white, while the underparts are reddish-brown. The tail is black. The Malacca flying squirrel (Parapteromys intermedius) inhabits Car Nicobar. This species can be considered the middle term between the other two, with a body length of 34 cm and a tail of 27 cm. Their underparts are white with a yellowish part in the center, while the upperparts are reddish-brown with darker tones in the rear and near the base of the tail. The tail is black with a small white tip.

Indian hawk-eagle (Accipteraetus shikra)
Order: Accipitriformes
Family: Accipitridae
Habitat: Tropical forests from Hindustan to Sunda Land, with incidental occurrence in Nicobar Islands. 
The human actions during the Holocene caused the decline of many species. However the species that were resilient enough survived, with their descendants now living in the Neocene. The shikra (Accipiter badius) had survived in the Indian subcontinent, giving rise to the Indian hawk-eagle. This species inhabits the tropical forests from Hindustan to Sunda Land, with incidental occurrence in Nicobar Islands. 


The Indian hawk-eagle has a body length of 70 cm and wingspan of 185 cm. Like nearly all birds of prey, the females are larger and heavier than the males. Adults have dark brown upperparts, a brown tail with six bars, a white patch in the wings that is visible in flight, white underparts, and a dark gray head with a white crown. 


Their diet consists of birds, lizards, snakes and mammals. The size of their mammalian prey ranges from rodents to monkeys. Individuals of the population living in Nicobar are capable of hunting Emperor junglefowl. Usually, a couple is capable of bringing down these large phasianids by working together. The male will distract the bird, while the female attacks from behind.


Indian hawk-eagles, like most but not all raptors, live solitarily or in pairs. Breeding territories are maintained through high circling, either by a solo adult or by a pair. Most displays occur in mid to late morning and are usually at fairly low heights with occasional calling. The breeding season starts in the summer. Nests are placed in relatively exposed branches, often being on the main crutch of the tree or the largest, most bare branch. They are made of twigs and lined with grass. The usual clutch is 2 to 3 eggs  which are pale bluish gray stippled on the broad end in black. The incubation period is 45 days and both parents help with it, but the female is the one that incubates for the longest time.


Like all birds of prey, the hatchlings are initially altricial. In this species, the chicks are still unable to lift their heads at 3 days old. By about two weeks of age, the young bird can start to stand on its folded leg within the nest. The begging calls will increase at about 3 weeks of age. They fledge within 95 days. At 12 weeks, the full juvenile plumage is attained. Despite the full plumage and powers of flight, the juvenile bird continues to linger in the vicinity of the nest, typically venturing no further than 150 m from the nest for months. The young eagles often continue to beg loudly for food, especially once their parents are in view, but if their crop is full they often retire to quietly sit in dense foliage. They reach sexual maturity with 7 years and have a lifespan of 27 years.

 Отправлено: 01.02.23 10:47. Заголовок: JOrnitho Very good!..

JOrnitho
Very good!

 Отправлено: 01.02.23 13:04. Заголовок: JOrnitho It's g..

JOrnitho
It's good! I like this.

 Отправлено: 01.02.23 18:24. Заголовок: Good translation!..

Good translation!

 Отправлено: 02.02.23 12:03. Заголовок: Thanks, everyone! I..

Thanks, everyone! I finished the description of the second flying squirrel genus. The next will be the rat.

Katchal flying squirrel (Microparapteromys agilis)
Order: Rodentia
Family: Sciuridae
Habitat: Forests of Katchal Island, tree canopy
During their expansion, the humans had introduced several species. The northern palm squirrel (Funambulus pennantii) was left by them on the Andaman Islands, where they survived to the transition between the Holocene and Neocene. In a case of evolutionary convergence to other rodents, their descendants had developed large membranes (or patagia) that span the space between the fore- and hindlimbs, and additional membranes connect the trailing edges of the hindlimbs with the proximal parts of the tail. These insular flying squirrels form the tribe Parapteromyini, which is formed by two genus: Parapteromys and Microparapteromys.

The genus Microparapteromys is formed by the dwarf insular flying squirrels. Differently from the Parapteromys, these small rodents are endemic to islands of the Archipelago of Nicobar. Their main representative is the Katchal flying squirrel, an inhabitant of the forested areas of small Katchal Island. This species is the typical representative of the group, with a head-to-body length of 15 cm and a tail of 12 cm. Their underparts are white, while the upperparts are dark brown. The tail is black and the head is light brown.

They feed mostly on fruit and nuts from trees, but will also eat insects, buds, mushrooms, bird eggs, nestlings, and flowers.

Like all representatives of the genus Microparapteromys, the Katchal flying squirrel is diurnal and solitary. The males and females only meet during the mating season, which happens during autumn. The gestation period is approximately 40 days. Young are born without fur or any capabilities of their own. Their ears open at 2 to 6 days old, and fur grows by 7 days. Their eyes do not open until they are 25 days old. Mothers wean their young 65 days after they are born. The young then become fully independent at around 120 days of age, sexual maturity is reached around this time. They have a lifespan of 4 years.

The genus Microparapteromys have other representatives:

Teressa flying squirrel (Microparapteromys minor) inhabits the forests of Teressa island. This species is the smallest representative of the genus, with a head-to-body length of 13 cm and a tail of 10 cm. Their underparts are whitish-yellow, while the upperparts and head are light brown. The tail is pale gray.

Camorta flying squirrel (Microparapteromys gracilis) inhabits the forests of Camorta island. This species have a head-to-body length of 15 cm and a tail of 11 cm. Their underparts are white, while the upperparts and head are dark brown. The tail is dark gray.

 Отправлено: 02.02.23 12:39. Заголовок: JOrnitho Interestin..

JOrnitho
Interesting animal.

 Отправлено: 02.02.23 14:23. Заголовок: Interesting animal!..

Interesting animal!