The biggest shark alive today, arriving at up to 20 meters in length, is the whale shark, a calm channel feeder. As of late as quite a while back, in any case, sharks of that scale probably incorporated the quick hunter megalodon, popular for its totally gigantic jaws and correspondingly colossal teeth.
We can only make inferences based on some of its living relatives, like the great white and mako sharks, due to incomplete fossil data regarding its size. However, we are now fairly certain, based on new research on its fossilized teeth, that it shared something else with these relatives: It appeared to maintain a body temperature above that of the surrounding ocean, indicating that it was not entirely cold-blooded.
Taking a temperature The majority of sharks, like the majority of fish, are ectothermic, which means that their body temperatures match the water’s. Yet, a modest bunch of animal varieties, a piece of a gathering named mackerel sharks, have a specific example of blood course that holds a portion of the intensity their muscles produce. Because of this, they are able to keep some parts of their bodies warmer than the rest of their body. The sub-Arctic waters that the salmon shark inhabits can keep its body temperature 20 degrees Celsius higher than normal.
Since Megalodon is a mackerel shark as well, some researchers have hypothesized that it must have been at least partially endothermic to maintain its growth rates in the various environments it inhabited. However, as previously stated, the megalodon remains that we have are insufficient to even determine the animal’s size, let alone whether it possessed the specialized circulatory structure required for shark endothermy.
Therefore, a group of researchers decided to directly examine the following items to determine whether it regulated its body temperature: its teeth.
The work depends on a peculiarity known as isotope bunching. In the event that a climate is sufficiently warm, the little weight contrasts between nuclear isotopes don’t make any difference, as the intensity is adequately warm to blend isotopes inside a material completely. However, heavier isotopes tend to pool together and form clumps within a material as temperatures drop. We now have tools that, with high resolution, can follow how isotopes are distributed within a material, giving us a direct measure of how clumpy it is. That, thusly, can be utilized to create a gauge of the temperature at which the material framed.
(This method has been used by scientists to estimate ancient temperatures in order to track how our climate is changing.)
The new research used fossil beds with at least three different kinds of fossils. There were clearly megalodon teeth in one. In any case, the others were expected to give some level of outside reference for the appraisals got from the sharks. These include the bones of known cold-blooded fish, which served as a starting point for determining the temperature of the environment. As a known warm-blooded control, they also obtained whale ear bone samples. Fundamentally, they got these examples from broadly dispersed destinations in the Atlantic and Pacific Seas, guaranteeing that any distinctions weren’t only a question of nearby natural circumstances.
Fasten your seatbelts! The ectotherm samples revealed typical regional variations in seawater temperatures, with estimates ranging from 17° C in California to 23° C in the Mediterranean. In contrast, the megalodon samples were always warmer than the cold-blooded samples, with an average difference of about 7° C. This isn’t as warm as the whale samples. Yet, as the scientists call attention to, the whale tests came from their inward ears, which are genuinely taken out from the climate, thus liable to mirror the creature’s inner temperature. In contrast, shark teeth are relatively exposed to the environment, suggesting that they may be somewhere in the middle of what is considered normal body temperature and what is found outside. Additionally, mackerel sharks’ body temperatures frequently fluctuate.
Therefore, why might a megalodon’s elevated body temperature have been chosen? There are two possible reasons. One possibility is that, as was mentioned earlier, the temperatures were necessary to maintain the growth rates required for megalodon development in non-tropical environments. Speed is the second. The animal may require warm muscles to propel itself through the water sufficiently quickly to be an effective predator. For instance, the mako shark is the fastest shark and is partially endothermic.
Megalodon’s huge body size could have likewise made heat maintenance fairly simpler, as it expands the proportion of body volume to surface region, importance there’s less surface to lose heat contrasted with how much muscle creating it.
The creators of the new paper, notwithstanding, recommend that could likewise have left megalodon powerless against environmental change. Megalodon may have been sensitive to changes in the ecosystem due to the high metabolic demands required to maintain its endothermy. Additionally, the Earth generally became cooler near the time of its extinction, resulting in lower sea levels that would have impacted coastal ecosystems. In addition, the megalodon appears to have grown up relying on coastal nurseries.
Disclaimer: The views, suggestions, and opinions expressed here are the sole responsibility of the experts. No Clear Insight Research journalist was involved in the writing and production of this article.
