During the Ice Age, which occurred from about 2.6 million to 11,700 years ago, many animals, particularly mammals, were indeed larger compared to their modern counterparts. There are several factors that may have contributed to the large size of Ice Age animals:
Abundant Resources: The Ice Age was characterized by extensive glaciation, which led to the formation of vast grasslands and tundra ecosystems. These environments provided abundant plant resources that supported large populations of herbivorous animals. The availability of ample food resources allowed these animals to grow to larger sizes.
Lower Predation Pressure: The larger size of some Ice Age animals could have provided an advantage in evading or defending against predators. While this is not a universal explanation, as many large predators also existed during the Ice Age, larger body size could have been an adaptive response to predation pressure in certain cases.
Energy Conservation: In cold environments, larger body size can be advantageous for thermal regulation. Larger animals have a lower surface-to-volume ratio, which helps reduce heat loss in cold climates. This energy-saving adaptation could have been beneficial during the Ice Age when temperatures were significantly lower than they are today.
Extinct Megafauna: Some of the largest Ice Age animals, such as mammoths, saber-toothed cats, and giant ground sloths, belonged to a group known as megafauna. These animals evolved and adapted to specific ecological niches over millions of years, resulting in their large size. However, many of these megafauna species became extinct at the end of the Ice Age, likely due to a combination of climate change and human hunting.
It's worth noting that not all Ice Age animals were large. There were also smaller species that adapted to the challenging environments of that time. The factors mentioned above are general trends that help explain the larger size of certain Ice Age animals, but the specific reasons for their size can vary depending on the species and their ecological niche.