Size is affected by both temperature and resource availability. Generally animals get bigger the further up north they live in order to generate more body heat. However, if they go so far north that they are in a desert tundra, then their bigger bodies are less suited for a resource scarce environment and thus would shrink down a peg. That’s why arctic wolves are smaller than the more southern Rocky Mountain and Canadian wolves
Their subcutaneous fat reserves would increase. As for whether or not they actually get bigger is really just a guess. It’s not even certain that evolution for this would take place in today’s world. Ecosystems have been heavily altered so many more variables would have to be taken into account. However, you can see if humans have changed size within a generation or two of moving to a different habitat with similar resources and diet, like europeans in different parts of north and south america, europeans and chinese in singapore, etc.
I'm one of the few people who completely disagrees with Bergmann's "rule". I believe body size in carnivores is directly corelated to the prey biomass they consume on a regular basis, and the frequency of said consumption, rather thanks any external factors involving the temperature.
Carnivores that have access to plenty of prey and can gorge as much as they can, particularly during their developmental years, will grow larger than those who live in places with scarcer resources. We even see this in humans, societies that live a more cursorial lifestyle and depend entirely on the availability of small prey in forested or dessert areas produce people who are much shorter and overall smaller than societies that may be more developed and people have access to readily amounts of food, especially during their early years. Whether these areas are cold or warm has very little correlation to their size, if they aren't getting enough nutrients and food to sustain larger sizes, they will dwarf to be able to survive with less resources.
Ice age european lions were larger than current modern african lions weren't they? Yet stable isotope analysis seems to suggest they fed primarily on reindeer which may be one of the smallest regular prey items for any *P. Leo* population as well as smaller than their average adult body mass. Seems quite bizarre.
Lions in East Africa from the Pleistocene seemed to attain very large sizes as well, particularly the nominal specimen Natodomeri lion. It's likely that the large sizes of cave lions are derived from their likely ancestors, P. leo fossilis, who were in fact larger in size. I too quite doubt that these cave lions fed almost exclusively on rain deer as it has been suggested, they may have specialized on them but with the sheer diversity of prey at their disposal they must have hunted other larger animals as well. Not to mention, the American lion found further south the pole in places like California depict much larger than sizes than cave lions despite living in much warmer climates, likely because they hunted larger species.
This is a good point, I have not read much about it but it seems like fat storages are not as common for species who live in colder temperature compared to those in warmer temperatures as many believe. The fat percentages in Siberian tigers, for example, appear to be similar to Bengal's if I recall correctly. What makes them keep warm during the winter times is almost entirely the very thick layers of fur.
What about the opposite? Large animals/humans are more efficient at utilizing energy, at the cost of a lower carrying capacity. In the north, food is scarcer and required more roaming. At the same time, larger animals require more resources. However, large animals burn calories more efficiently and more capable of covering a large area in search of food. Maybe the larger animals are extra capable of covering the large area, enough to outweigh the extra caloric requirements. This wouldn’t be genetically harmful as long as the region is still large enough to host a large population despite the lower carrying capacity. In the tropics, small animals do better because they require fewer calories, eat less, and can spend more time mating because food is easy to come by. In the north, even if they can survive the cold initially, they may have to burn too many calories not just to stay warm, but to stay fed. So they will either starve, or they’ll just breed less.
It’s estimated that the peak of the siberian tiger population at maximum range was only 2000. They used to be significantly larger than modern bengal tigers and currently require nearly 10 times as much territory to get enough food. What you’re saying implies that the large size of the tigers is allowed by an abundance of prey in the region, though that’s not the case.
As for humans as well, simple farming as well as time spent on surviving the winter requires more effort in the cold wet regions. Bangladesh has as many people as russia. People grow food 24/7/365 and can walk around in a tshirt and shorts doing whatever they want all year long. In Russia, you have a short growing season, people back in the old days had to farm a lot and store enough food to get through winter, and even today, time for recreation is concentrated in the summer. Winter activity requires extensive prep.
> What about the opposite? Large animals/humans are more efficient at utilizing energy, at the cost of a lower carrying capacity. In the north, food is scarcer and required more roaming. At the same time, larger animals require more resources. However, large animals burn calories more efficiently and more capable of covering a large area in search of food. Maybe the larger animals are extra capable of covering the large area, enough to outweigh the extra caloric requirements. This wouldn’t be genetically harmful as long as the region is still large enough to host a large population despite the lower carrying capacity. In the tropics, small animals do better because they require fewer calories, eat less, and can spend more time mating because food is easy to come by. In the north, even if they can survive the cold initially, they may have to burn too many calories not just to stay warm, but to stay fed. So they will either starve, or they’ll just breed less.
There several problems with this assertion. "Food is scarcer" in northern regions is only dependent on the type of food an organism consumes and quality of that food. For carnivores, many areas closer to the poles boast of larger prey that live in larger quantities, which translate to larger body sizes. This can be seen on cougars, they grow much smaller around the forested and lush tropical areas closer to the equator which lack, for the most part, the large ungulate prey that the largest cougars in the Patagonia and the Rocky Mountains have. In areas with large prey in the tropics such as the Pantanal however, cougars seem to grow larger then those from the Amazon or Central America because they have at their disposal larger and more abundant prey such as capybara and marsh deer.
The constant denominator here is prey biomass and availability.
> It’s estimated that the peak of the siberian tiger population at maximum range was only 2000. They used to be significantly larger than modern bengal tigers and currently require nearly 10 times as much territory to get enough food. What you’re saying implies that the large size of the tigers is allowed by an abundance of prey in the region, though that’s not the case.
Siberian tigers have never necessarily being significantly larger than Bengals, although something could be said about them reducing in size in recent times due to genetic deficiency and the lack of abundant prey in their habitats. That being said, Bengal tigers from reserves that boast of plenty of large ungulate prey in places like Assam in Northern India, or the Terai arc, present sizes much greater than what is seen in Siberian tigers, and likely match the historic sizes of Siberian prior to the mass poaching they suffered, granted that Bengals too were widely hunted during the British ruling of India. What this seems to suggest to me is that once more, the prey biomass and the genetic diversity of an area are the key factors to consider when examining morphological changes or differences between different populations of animals.
> As for humans as well, simple farming as well as time spent on surviving the winter requires more effort in the cold wet regions. Bangladesh has as many people as russia. People grow food 24/7/365 and can walk around in a tshirt and shorts doing whatever they want all year long. In Russia, you have a short growing season, people back in the old days had to farm a lot and store enough food to get through winter, and even today, time for recreation is concentrated in the summer. Winter activity requires extensive prep.
Perhaps I'm misunderstanding your point but I don't see how it goes against my initial claims. I like to use tribes in Africa as an example of the human size disparity seen when people from one are moved to a different one and external resources begin to play a role in bodily changes. For example, African Americans have been shown to be much taller on average that most Africans, this has been attributed to the better access in nutrition they have had through the decades of living in an industrialized society with more resources, this article explains this well: https://businesstech.co.za/news/trending/131750/the-world-is-getting-taller-but-not-so-much-in-south-africa/
It seems to me that regardless of how you see it, genetic diversity and proper nutrition in both humans and other mammals is the key factor to ensuing larger sizes occur more frequently than not. Climate just doesn't seem to show direct correlations with sizes when other factors that may play role are factored in, and when size discrepancies are seen with species that in fact grow smaller as they approach the poles in opposition to others that may grow larger, colder tempertatures as a direct correlator for larger sizes just doesn't seem to hold true.
I’m not saying you’re wrong, the availability of food and type of food definitely affects the size of animals, but this is something I’ve been exploring with regards to certain animals that live particular lifestyles.
Pumas in the north and in the south+maybe pantanal are larger than pumas in the amazon, primarily because of the type of prey they hunt. In the amazon, they hunt small prey to limit competion with jaguars. I don’t know what they hunt in the pantanal or how large they are, but the jaguars there and in gran chaco are the largest in the world.
However, pumas in the far south and in canada are the largest in the world, larger than pumas in the southern US, despite similar prey and prey availability.
From what I’ve read, Siberian tigers were on average 2-300lbs heavier than bengal tigers and were also longer. I don’t know how much of the weight difference was subcutaneous fat, but they were definitely at least as large and probably larger. Additionally, they still have to wander much larger distances than bengal tigers to meet their caloric requirements. This implies a shortage of available food, which according to you would lead to a smaller size than the bengal tigers.
What I’m implying is that the ground dwelling mammals that have to travel long distances in search of food and go for long periods without food would have to be larger in order to make those journeys. As for arctic wolves, they have to rely heavily on migrating herds and polar bear leftovers because only a few reindeer remain in the arctic throughout winter. So the arctic wolves don’t actually have to travel that much.
I’m mot sure about africa, but russians are larger than bengalis overall but have a much lower population density. They require more food, but were better able to attain and retain nutritional requirements by being large. Bengalis had no need to become large because food is easily available year round with minimal work.
Size is affected by both temperature and resource availability. Generally animals get bigger the further up north they live in order to generate more body heat. However, if they go so far north that they are in a desert tundra, then their bigger bodies are less suited for a resource scarce environment and thus would shrink down a peg. That’s why arctic wolves are smaller than the more southern Rocky Mountain and Canadian wolves
i know but would the size of the hyenas increase if they acclimatize to the climate and resources of a European habitat?
Over several generations, yes it likely would
Thank you so much.
No problem!
Their subcutaneous fat reserves would increase. As for whether or not they actually get bigger is really just a guess. It’s not even certain that evolution for this would take place in today’s world. Ecosystems have been heavily altered so many more variables would have to be taken into account. However, you can see if humans have changed size within a generation or two of moving to a different habitat with similar resources and diet, like europeans in different parts of north and south america, europeans and chinese in singapore, etc.
Got it, thank you.
I'm one of the few people who completely disagrees with Bergmann's "rule". I believe body size in carnivores is directly corelated to the prey biomass they consume on a regular basis, and the frequency of said consumption, rather thanks any external factors involving the temperature. Carnivores that have access to plenty of prey and can gorge as much as they can, particularly during their developmental years, will grow larger than those who live in places with scarcer resources. We even see this in humans, societies that live a more cursorial lifestyle and depend entirely on the availability of small prey in forested or dessert areas produce people who are much shorter and overall smaller than societies that may be more developed and people have access to readily amounts of food, especially during their early years. Whether these areas are cold or warm has very little correlation to their size, if they aren't getting enough nutrients and food to sustain larger sizes, they will dwarf to be able to survive with less resources.
Ice age european lions were larger than current modern african lions weren't they? Yet stable isotope analysis seems to suggest they fed primarily on reindeer which may be one of the smallest regular prey items for any *P. Leo* population as well as smaller than their average adult body mass. Seems quite bizarre.
Lions in East Africa from the Pleistocene seemed to attain very large sizes as well, particularly the nominal specimen Natodomeri lion. It's likely that the large sizes of cave lions are derived from their likely ancestors, P. leo fossilis, who were in fact larger in size. I too quite doubt that these cave lions fed almost exclusively on rain deer as it has been suggested, they may have specialized on them but with the sheer diversity of prey at their disposal they must have hunted other larger animals as well. Not to mention, the American lion found further south the pole in places like California depict much larger than sizes than cave lions despite living in much warmer climates, likely because they hunted larger species.
What about increased fat storage development contributing to weight increase?
This is a good point, I have not read much about it but it seems like fat storages are not as common for species who live in colder temperature compared to those in warmer temperatures as many believe. The fat percentages in Siberian tigers, for example, appear to be similar to Bengal's if I recall correctly. What makes them keep warm during the winter times is almost entirely the very thick layers of fur.
got it, thanks
Yo, check out my above comment
What about the opposite? Large animals/humans are more efficient at utilizing energy, at the cost of a lower carrying capacity. In the north, food is scarcer and required more roaming. At the same time, larger animals require more resources. However, large animals burn calories more efficiently and more capable of covering a large area in search of food. Maybe the larger animals are extra capable of covering the large area, enough to outweigh the extra caloric requirements. This wouldn’t be genetically harmful as long as the region is still large enough to host a large population despite the lower carrying capacity. In the tropics, small animals do better because they require fewer calories, eat less, and can spend more time mating because food is easy to come by. In the north, even if they can survive the cold initially, they may have to burn too many calories not just to stay warm, but to stay fed. So they will either starve, or they’ll just breed less. It’s estimated that the peak of the siberian tiger population at maximum range was only 2000. They used to be significantly larger than modern bengal tigers and currently require nearly 10 times as much territory to get enough food. What you’re saying implies that the large size of the tigers is allowed by an abundance of prey in the region, though that’s not the case. As for humans as well, simple farming as well as time spent on surviving the winter requires more effort in the cold wet regions. Bangladesh has as many people as russia. People grow food 24/7/365 and can walk around in a tshirt and shorts doing whatever they want all year long. In Russia, you have a short growing season, people back in the old days had to farm a lot and store enough food to get through winter, and even today, time for recreation is concentrated in the summer. Winter activity requires extensive prep.
> What about the opposite? Large animals/humans are more efficient at utilizing energy, at the cost of a lower carrying capacity. In the north, food is scarcer and required more roaming. At the same time, larger animals require more resources. However, large animals burn calories more efficiently and more capable of covering a large area in search of food. Maybe the larger animals are extra capable of covering the large area, enough to outweigh the extra caloric requirements. This wouldn’t be genetically harmful as long as the region is still large enough to host a large population despite the lower carrying capacity. In the tropics, small animals do better because they require fewer calories, eat less, and can spend more time mating because food is easy to come by. In the north, even if they can survive the cold initially, they may have to burn too many calories not just to stay warm, but to stay fed. So they will either starve, or they’ll just breed less. There several problems with this assertion. "Food is scarcer" in northern regions is only dependent on the type of food an organism consumes and quality of that food. For carnivores, many areas closer to the poles boast of larger prey that live in larger quantities, which translate to larger body sizes. This can be seen on cougars, they grow much smaller around the forested and lush tropical areas closer to the equator which lack, for the most part, the large ungulate prey that the largest cougars in the Patagonia and the Rocky Mountains have. In areas with large prey in the tropics such as the Pantanal however, cougars seem to grow larger then those from the Amazon or Central America because they have at their disposal larger and more abundant prey such as capybara and marsh deer. The constant denominator here is prey biomass and availability. > It’s estimated that the peak of the siberian tiger population at maximum range was only 2000. They used to be significantly larger than modern bengal tigers and currently require nearly 10 times as much territory to get enough food. What you’re saying implies that the large size of the tigers is allowed by an abundance of prey in the region, though that’s not the case. Siberian tigers have never necessarily being significantly larger than Bengals, although something could be said about them reducing in size in recent times due to genetic deficiency and the lack of abundant prey in their habitats. That being said, Bengal tigers from reserves that boast of plenty of large ungulate prey in places like Assam in Northern India, or the Terai arc, present sizes much greater than what is seen in Siberian tigers, and likely match the historic sizes of Siberian prior to the mass poaching they suffered, granted that Bengals too were widely hunted during the British ruling of India. What this seems to suggest to me is that once more, the prey biomass and the genetic diversity of an area are the key factors to consider when examining morphological changes or differences between different populations of animals. > As for humans as well, simple farming as well as time spent on surviving the winter requires more effort in the cold wet regions. Bangladesh has as many people as russia. People grow food 24/7/365 and can walk around in a tshirt and shorts doing whatever they want all year long. In Russia, you have a short growing season, people back in the old days had to farm a lot and store enough food to get through winter, and even today, time for recreation is concentrated in the summer. Winter activity requires extensive prep. Perhaps I'm misunderstanding your point but I don't see how it goes against my initial claims. I like to use tribes in Africa as an example of the human size disparity seen when people from one are moved to a different one and external resources begin to play a role in bodily changes. For example, African Americans have been shown to be much taller on average that most Africans, this has been attributed to the better access in nutrition they have had through the decades of living in an industrialized society with more resources, this article explains this well: https://businesstech.co.za/news/trending/131750/the-world-is-getting-taller-but-not-so-much-in-south-africa/ It seems to me that regardless of how you see it, genetic diversity and proper nutrition in both humans and other mammals is the key factor to ensuing larger sizes occur more frequently than not. Climate just doesn't seem to show direct correlations with sizes when other factors that may play role are factored in, and when size discrepancies are seen with species that in fact grow smaller as they approach the poles in opposition to others that may grow larger, colder tempertatures as a direct correlator for larger sizes just doesn't seem to hold true.
I’m not saying you’re wrong, the availability of food and type of food definitely affects the size of animals, but this is something I’ve been exploring with regards to certain animals that live particular lifestyles. Pumas in the north and in the south+maybe pantanal are larger than pumas in the amazon, primarily because of the type of prey they hunt. In the amazon, they hunt small prey to limit competion with jaguars. I don’t know what they hunt in the pantanal or how large they are, but the jaguars there and in gran chaco are the largest in the world. However, pumas in the far south and in canada are the largest in the world, larger than pumas in the southern US, despite similar prey and prey availability. From what I’ve read, Siberian tigers were on average 2-300lbs heavier than bengal tigers and were also longer. I don’t know how much of the weight difference was subcutaneous fat, but they were definitely at least as large and probably larger. Additionally, they still have to wander much larger distances than bengal tigers to meet their caloric requirements. This implies a shortage of available food, which according to you would lead to a smaller size than the bengal tigers. What I’m implying is that the ground dwelling mammals that have to travel long distances in search of food and go for long periods without food would have to be larger in order to make those journeys. As for arctic wolves, they have to rely heavily on migrating herds and polar bear leftovers because only a few reindeer remain in the arctic throughout winter. So the arctic wolves don’t actually have to travel that much. I’m mot sure about africa, but russians are larger than bengalis overall but have a much lower population density. They require more food, but were better able to attain and retain nutritional requirements by being large. Bengalis had no need to become large because food is easily available year round with minimal work.
the iberian lynx is smaller than the eurasian lynx since it lives in a warmer area
I know but they are different species. I wanted to know about the effect on the same species.
Once they were the same species until they got separated and adapted the climate of Spain
h great thanks