Tarsiers' unique features have caused people to call the little primates a variety of names since their discovery in the late 18th century: everything from Gremlins and Baby Yoda to Blarp, that tragic CGI alien ape from the 1998 film "Lost in the World." Space".
So what is a tarsier and what are their unusual characteristics that make them eerily comparable to some of Hollywood's most notable characters?
The tarsier is a small species of primate found in the forests of Southeast Asia. There are 16 species of tarsiers and they occupy the dense forests of Malaysia, Indonesia, Brunei and the Philippines. And about those strange features that gave them their nicknames: maybe it's the fact that they can rotate their heads 180 degrees? That's a good start. But the most likely reason is the disproportionate proportion of the eyeball to the head.
Content
- Tarsiers are fascinating primates
- Wow, what big eyes you have
- Lemur, Monkey or Monkey?
- Tarsiers do best in their habitats
Tarsiers are fascinating primates
For Myron Shekelle, Ph.D., an instructor and research associate in the biology department at Western Washington University, tarsiers are much more than a strange combination of characteristics; they are a fascinating example of primate evolution. Shekelle has conducted decades of research contributing to what we know about tarsiers and primate evolution.
“When I turned in my first grant proposal, which would have been in 1993 or 1994, one of the reviewers commented, 'Shekelle has outlined a career worthy of research,' and now... I'm about to get to the point where I can publish the answer to the questions I posed in that research grant proposal so many years ago,” he says.
Although each species has different characteristics, tarsiers tend to range in size from 3 to 6 inches long, with tails that can be twice that length, making them one of the smallest known primates. Some tarsier species have hairless, mouse-like tails, while others have tufts of fur along the length of the tail or at the tip.
Tarsiers, like owls, can rotate their heads 180 degrees and have round, furry bodies with very long legs. The ankle bones (tarsi) are particularly long – this is where the name, tarsier, comes from. Their long legs and ankles allow them to hop and leap like lemurs. Their fingers are also exceptionally long, with small sticky pads on the tips to help them cling to the trees where they live and hunt for prey.
They are the only primate species on the planet that is entirely carnivorous. They eat the best Southeast Asian forests have to offer, including insects, lizards and even snakes.
Wow, what big eyes you have
It's impossible to talk about tarsiers without also discussing their big eyes. Even for nocturnal mammals, their eyes are huge compared to their body size – they are the largest eyes of any mammal relative to body weight. Tarsiers do not have a tapetum lucidum, a reflective eye layer that most other nocturnal animals have.
“One of the things we know is that when you take your flashlight and shine it into a forest at night, many animals have a very bright glow in their eyes that comes right back at you. Cats and dogs, lemurs, bushbabies and lorises,” Shekelle explains. “Tarsiers don’t have that. [Humans], monkeys and apes don’t have that.”
The tapetum lucidum is important for night vision because it creates more chances for the retina to capture light. “So the tarsier's eye had to compensate and became much larger than one would expect,” explains Shekelle.
He says the tarsier's lack of this reflective layer offers researchers interesting insight into primate evolution. When primates became diurnal, that is, active during the day, they eventually lost the need for a tapetum lucidum.
“So it appears that tarsiers spent some time in their history as diurnal primates. If they later reversed and became nocturnal again, perhaps they had already lost that tapetum lucidum”, says Shekelle.
Lemur, Monkey or Monkey?
In 1994, Shekelle and his colleagues identified several new species of tarsier on the Indonesian island of Sulawesi, where only one species was thought to exist. Since the first scientific description of tarsiers was published around 1777, scientists have debated where tarsiers belong on the primate evolutionary tree.
They jump, climb and live like lemurs. In contrast, they have similar characteristics to monkeys and humans, such as a lack of tapetum lucidum.
“At the level of genomic data, where we can see really important changes, the evidence is becoming clearer that tarsiers are our cousins, related to monkeys, apes and humans, and belong to a group we call Haplorhini,” said Shekelle . explains.
Wait – tarsiers are ours cousins? Based on the available data, Shekelle says yes, that's what the data shows.
Tarsiers do best in their habitats
Tarsiers are notoriously elusive and difficult to study, especially without the deadly glow that other nocturnal species have. Don't bet on seeing them at the zoo either, because they do poorly in captivity.
“Each group that was taken into captivity saw its population decline very quickly or less quickly, but they all eventually die,” explains Shekelle. “I don’t think it has to be this way.”
Tarsier conservation is becoming an increasingly important topic, as some tarsier species have entered the endangered or vulnerable species list due to their small size, limited population, lack of protected areas, and deforestation and mining. . The island of Sangihe in Indonesia has an endemic species of tarsier – the Sangihe tarsier ( Tarsius sangirensis ) – meaning they are only found there. The Sangihe tarsier was recently added to the list of the world's 25 most endangered primates after the island was opened to gold mining.
Because there are more tarsier species than there are scientists who study them, Shekelle says it's difficult to know precisely to what extent some species are threatened on these many islands. In fact, he says there is an even smaller island between Sangihe and Sulawesi called Siau Island. It's only about 100 square kilometers and is home to a critically endangered species he wrote about in 2008 called Tarsius tumpara .
Shekelle hopes that more tarsier species won't become critically endangered with some intentional conservation efforts.
“If we keep tarsiers in their habitat, like in Indonesia, and just put a 'cage' around them and use someone who really knows how to keep them alive,” says Shekelle, “they stay alive and reproduce.”
It is a systematic process to place tarsiers in a properly controlled environment that requires time, experience and financial investment.
Now this is interesting
Tarsiers are some of the oldest primates on the planet. Fossil records show that they lived all over the world, including in North America and Europe, and date back at least 55 million years.
