Scientists believe that if the surrounding cold environment can properly reduce the body temperature of animals, it can play an anti-aging and longevity role; If the surrounding cold environment can't lower the body temperature of animals, there is no obvious anti-aging and longevity effect.
For example, for temperature-changing animals (such as fish), because their body temperature can be reduced due to the reduction of environmental temperature (water temperature), reducing environmental temperature can slow down their aging speed.
However, for warm-blooded animals (such as mammals and humans), because their body temperature will not be reduced due to the reduction of environmental temperature (for example, human body temperature is basically maintained at around 37℃ in winter and summer), the effect of reducing their environmental temperature on anti-aging is not very significant. So some marine life has a long life.
Polar bears live longer than brown bears.
In addition, scientists have long noticed a phenomenon that the life span of large animals is often longer than that of small animals. The situation of plants is similar. Tall plants usually live longer than short plants.
For example, an elephant's heartbeat is only 26 times per minute, and its average life expectancy is 80 years. The heartbeat of blue whales can be as low as 2 times per minute (when diving), and the average life expectancy is 90 years; The rat's heartbeat can reach 500 beats per minute, and its life span is only three years.
This is because a small body will dissipate heat very quickly, so it needs a higher metabolic rate to maintain body temperature. For example, the smallest hummingbird has a heartbeat of more than 3000 times per minute, which also leads to their very fast metabolic rate. In order to get a huge amount of food to maintain this metabolic rate, they must eat hundreds of flowers every day. The faster the metabolism, the faster the cell renewal. Every animal's cell renewal is fixed, and it is easy to update cells too quickly.
In addition, reducing energy intake (that is, minimizing exercise) can also slow down metabolism and prolong life. When animals are hungry, they will reduce reproduction and use energy to supply and repair cells, thus improving the state of disease-resistant genes and enhancing their ability to resist disease and aging.
Olm can stay still for seven years in a row.
Sexual maturity will affect life expectancy sooner or later. For example, animal behavior is regulated by hormones, and animals with early sexual maturity show strong reaction to external stimuli, often showing a provocative behavior, which will lead to a large number of cell deaths and shortened life span; If you can inhibit the secretion of sex hormones or delay sexual maturity, your life may be prolonged accordingly.
Under this comprehensive factor, you can know why Greenland sleeping shark can live to 500 years old. Greenland sleeping shark 150 years old is sexually mature, slow in movement, slow in metabolism, living in a cold environment and slow in heartbeat. So is the longevity champion turtle.
However, mammals need to hunt animals all the year round to avoid natural enemies and maintain the continuation of the population through reproduction, so the average life expectancy is not high. Humans are a special case of mammals, and will improve their life span through health care, drugs and diet intake.
So what is the longest-lived mammal? This is a bowhead whale. Scientists estimate the age of animals by analyzing the proportion of D-amino acids in the lens of bowhead whales, and find that their life span can exceed 200 years. You know, blue whales can live to about 100 at most.
Bowhead whales, also known as Greenland right whales, are fin whales. They have no teeth, but they have bone plates similar to bones, which can help them filter food from the water. This whale lives in the North Pole. Adult bowhead whales can grow to 65,438+08 meters long and weigh more than 65,438+000 tons. Such a huge animal shows almost no signs of age-related diseases that plague other animals, including humans.
You know, its cell number is more than 1000 times that of human beings. The more cells there are, the more likely they are to make mistakes when they are updated, and then they will die easily. You know, even close relatives of bowhead whales? Minke whales much smaller than them can only live for 50 years.
So scientists believe that bowhead whales, like bats, have evolved a special natural mechanism to help them resist cancer and aging. Bat's metabolism is very fast, but because of its super DNA repair ability, even if the cell update is wrong, it can be repaired quickly, thus longevity.
In a study to reveal the secret of this giant whale's longevity, researchers compared the genome of this whale with that of nine other mammals, including other whales, cows, mice and humans. Scientists have found that mutations in two genes make bowhead whales live longer.
One of its genes is considered to be anticancer, and it is also related to aging and DNA repair. Another gene is related to DNA repair.
Genetic advantages, coupled with the slow swimming speed of bowhead whales, make their metabolism slow, live in the Arctic and its adjacent waters all their lives, and their sexual maturity is relatively late. Bowhead whales reach sexual maturity at the age of 10 to 15. The mating period is from March to August every year, and every 3-4 years, the mother whale will give birth to a calf, which is very mature among the mother whales. This calf is about 4.5 meters long and weighs 1 metric ton. Various factors make bowhead whales live longer.
Because of the long life span, females still have the ability to mate and give birth at the age of 90, which is unique among mammals, and this also ensures that bowhead whales can better ensure the continuation of the population when they are pregnant for such a long time. Of course, there is another bad problem. Because of the long life span, women may also have menopause. The fact that a very large individual has no cubs around confirms this.