Wombats can slow their heart rate to just 40 beats per minute to save energy.

Wombats are herbivorous marsupials native to Australia that possess one of the lowest metabolic rates among mammals. Research conducted by institutions like the University of Adelaide shows that their resting metabolic rate is approximately 25% to 30% lower than most placental mammals of a similar size. This physiological adaptation is a direct response to their diet of tough, fibrous, and nutrient-poor native grasses.During periods of rest or inside their burrows, a wombat's heart rate can drop to as low as 40 beats per minute. This bradycardia helps minimize oxygen consumption and heat production, allowing them to remain sedentary for long periods without needing frequent meals. Their digestion is equally slow, taking up to 14 days for a single meal to pass through their system to maximize nutrient extraction.The burrowing lifestyle of the wombat also plays a role in this energy conservation strategy. Burrows provide a stable microclimate that protects them from the extreme temperature fluctuations of the Australian bush. By maintaining a low heart rate and metabolic state within these shelters, wombats can survive prolonged droughts and seasonal food shortages that would be fatal to more active herbivores.Studies published in journals such as 'Physiological and Biochemical Zoology' highlight that this low-energy lifestyle is essential for the three extant species: the Common Wombat, the Southern Hairy-nosed Wombat, and the critically endangered Northern Hairy-nosed Wombat. These animals have evolved to prioritize efficiency over speed, making them masters of survival in nutrient-limited ecosystems.