The largest elephant ever recorded weighed 13 tons ... Fin whales weigh up to 50 tons - but weight is buoyed by water enabling it to exist.
Some thing must have been different 100 million years ago for something to stand up, breath, and pump blood with out being crushed by its shear weight:
2. The Paradox of Large Dinosaurs and Flying Pterosaurs
Applying Science to Understanding Large Dinosaurs
https://dinosaurtheory.com/big_dinosaur.html
Modern scientific discoveries may give us some clues as to why the pre-flood world was so different. Scientists have discovered air bubbles that have been trapped in fossilized amber (tree sap). As the tree sap rolled down the side of the tree, it captured the atmosphere in these air bubbles, which when analyzed reveals an earlier atmosphere had about 35 percent oxygen compared to today's 21 percent.
According to the fossil record, many plants and animals were of much greater size than those we see today. Dragonflies had wingspans of over 3 feet, cockroaches were 18 inches long and cattails grew to be 60 feet tall. While we may never know for sure why all of these things occurred, we know that when God said His creation was “very good,” it was indeed, very good.
In addition to the increased oxygen, other studies have suggested that there was a greater air pressure as well. New Scientist magazine, which comes from an evolutionary perspective, explains: One implication is that the atmospheric pressure of the Earth would have been much greater during the Cretaceous Era, when the bubbles formed in the resin. A dense atmosphere could also explain how the ungainly pterosaur, with its stubby body and wingspan of up to 11 meters, could have stayed airborne. The spread of angiosperms, flowering plants, during the Cretaceous era could have caused the high oxygen levels.
Hyperbaric chambers are producing some amazing health benefits. The Mayo Clinic has used hyperbaric chambers for treatments of wounds that won’t heal, decompression sickness, infections, and the release of growth factors and stem cells. Hyperbaric treatment can also be very helpful with carbon monoxide poisoning, smoke inhalation, gas gangrene, crush injuries, necrotizing (premature death of cells), soft tissue infections, compartment syndrome, compromised skin grafts, and enhanced healing in diabetic wounds.
Not only is this artificial “atmosphere” good for the body, it also seems to be wonderful for plants. At Keio University in Tokyo, Japan, Dr. Kei Mori placed a cherry tomato plant in a similar chamber where he filtered out ultraviolet light and increased the pressure so the plant would take in carbon dioxide faster. The results were astounding. In two years his cherry tomato plant was 14 feet tall and had over 900 tomatoes that were baseball size. The plant went on to be over 45 feet tall and yielded around 15,000 tomatoes. This result may help explain why we see such large plants in the fossil record. In fact, some have suggested that if our pre-flood atmosphere was like a hyperbaric chamber today, not only would it produce the large vegetation seen in fossils but, it may also have contributed as one factor of why people had such long lifespans before the flood of Noah.