When you look at the reconstruction of the skeleton and the brain of Neoepiblema acreensis, a generation of genus Go & # 39; ay, it is difficult to shake the feeling that something is not right.
In the back of the skeleton skeleton, the giant brain in the direction of South America looks really, really small. On some estimates, it was about three to five times less than scientists expected from a body weight of up to 180 pounds, and comparable to modern rats. In fact, 10 million years ago the animal may have been circulating in the brain of half an orange called & # 39; mandarin orange & # 39 ;, according to a letter published Wednesday in the Biology Letter.
The glory days of rats, in terms of size of animals, were long ago, said Leonardo Kerber, a psychologist at the Universidade Federal de Santa Maria in Brazil and co-author of the new study. Today the rats are generally pretty, except for major innovations such as & # 39; milk & # 39; which can weigh up to 150 pounds. But in relation to the relative size of the brain, N. acreensis, which represents this fossil skeleton dating back to the 1990s in the Amazon Brazilians, appears to be extreme.
Researchers used body mass index and brain weight in modern South American rats to find the size of a ballpark in N. acreensis, after which the mean brain mass was equal to the volume of head holes. The first method predicted a weight gain of 4 ounces, but the volume suggested 1.7 ounces. Other calculations, used to compare the expected proportion of brain and body size and actual size, suggested that N. acreensis & # 39; s three or five times less than expected.
There is some uncertainty about the process of petrol filling psychotherapy, Dr. Kerber warned. But making a reasonable assessment of that effect did not significantly affect the overall picture: This mindset was less.
Mental great benefit & # 39; interest, but it may take many calories to maintain, so it makes sense to have one adult looga needed. Probably one reason for N. acreensis Kerber said: "If such a small creature were alive it would have been a # 39; hunted in South America before it came too fast, hunting like chickens," said Dr. Kerber. The first hunters may have been. big, crocodile-looking animals prefer to wait. Special area may be caused by old mouse's brain a little misleading – and easy to care for, but just large enough to help prevent the predators looga loose.
When looking at the size of the brain and body size of other rats, researchers have found another manufacturer, an animal that still lives today: Cuba meat, weighing no more than 19 pounds. His mind is also spontaneous, which is consistent with the idea that brain size may be related to stress from prediction. Like N. acreensis, the island's hutia may not be associated with large, aggressive animals as it returns.
Dr. Kerber said: "This is a fantasy, that there are some behavioral effects. Due to lafagurinayaan researchers measure the brain of rodents, especially older models, like to see this approach as well.