Nobody expected it, but that is precisely the conclusion of a study published in the journal Science Advances: global warming could reduce the size of mammals, just as it happened about 56 million years ago, about 10 million years after the dinosaurs became extinct. You can read more about this in our article on the origin of global warming.
At that time, Earth's temperature increased between 5 and 8 degrees Celsius in 10.000 years, and stayed elevated for 170.000 years before returning to normal.
An example of "dwarfing" was found in Siphrhippus, which was the first equid. This animal shrunk by at least 30% during the first 130.000 years of warming. As the Earth's temperature returned to normal, its body size grew by 76%. But it's not alone. Researchers have shown that this pattern is maintained even in events where the warming is not so great, like the one the planet is experiencing today.
That's why researcher Abigail D'Ambrosia of the University of New Hampshire said, "Unfortunately, today is a big experiment." The question is, why? In areas where the climate is warmer, mammals tend to be smaller than in cooler ones. D'Ambrosia explains that when temperatures are high, the smaller size is more efficient for the body, as it can cool down better. To better understand this dynamic, it is advisable to read about how heat affects animals.
Although there are other reasons why animals may become smaller, such as lack of food or water, temperature is a cause that affects all living beings. Thus, according to the study, many of the species we know today could be smaller in the future. For more information on how climate will influence fauna in general, it is interesting to consult the study on the effects of climate change on Europe's flora and fauna.
In the current context, global warming is occurring at an unprecedented rate, raising serious concerns about how it will affect biodiversity and ecosystem structure. According to a recent study by the University of Granada and the Pontifical Catholic University of Chile, metabolic restrictions resulting from rising temperatures have been shown to limit the development of many organisms, preventing them from reaching large sizes. This phenomenon has been observed in several animal groups, and its impact extends across different classes and species.
An analysis of 637 empirical measurements of thermal tolerance and size, including annelids, mollusks, arthropods, and other groups, has allowed researchers to formulate an equation that could quantify heat tolerance in ectotherms. Research indicates that smaller animals have a greater tolerance to extreme heat compared to larger ones. This divergence can be explained in terms of the relationship between size and thermal sensitivity; although larger animals can withstand high temperatures for longer, their development and growth are compromised when faced with extreme climatic conditions.
The importance of this phenomenon is not merely theoretical; it has practical applications that can influence natural resource management, conservation, and biodiversity planning. For example, the size of marine organisms is a crucial factor for the fishing industry, and changes in fish size can impact the local economy and food security. This is related to the effects of global warming in the economy and food security.
Studies also indicate that this pattern of size reduction could influence ecosystem dynamics, including competition between species. For example, it has been shown that under conditions of high competition, species tend to reduce their size as they adapt their survival strategies. This could be a result of selective pressure imposed by the environment. In this sense, it is interesting to explore alterations in natural selection that are occurring due to global warming.
Likewise, at the cutting edge of evolutionary history, significant changes in mammal size have been documented over time. During the early Eocene, for example, many herbivorous mammals were observed to become smaller, coinciding with periods of global warming. This indicates that mammal size has been closely linked to climatic conditions over millennia. If you want to better understand global warming, you can consult the article on differences between climate change and global warming.
On the other hand, global warming is not occurring uniformly in all regions of the planet. Tropical areas and other warming ecosystems have been observed to be experiencing more drastic changes. The animal populations that live in these regions are the most vulnerable, and their heat tolerance limits may be closer than in other areas. For a deeper understanding, it is helpful to explore how other groups behave in similar situations, as detailed in the article on amphibians and climate change.
The ecological implications of these findings are enormous, putting not only individual species at risk, but also ecosystems as a whole. This issue highlights the need for further research into how climate change impacts mammal size. Therefore, it is imperative that further research be conducted to fully understand these changes and their effects on biodiversity. Conservation strategies must be adapted to mitigate these effects. An interesting aspect is how climate change affects ecosystems, which can be consulted in clean air and its consequences.
Both global warming and mammalian responses to this phenomenon are intrinsically linked. Species that fail to adapt to these changes may face extinction, while those that survive could experience significant changes in their morphology and behavior. The relationship between body size and climate adaptation is one of the most fascinating and troubling areas of modern biology.
