00:00 [MUSIC PLAYING]
00:03 This wild-looking creature is one of the largest shark
00:06 species known, called the basking shark,
00:08 or what is sometimes referred to as the filter-feeding shark.
00:11 While it might look outlandish, it
00:13 has an even more outlandish quality,
00:15 according to marine biologists.
00:16 Unlike 99.9% of other shark and fish species,
00:20 it's not entirely cold-blooded.
00:22 In the last half century, it was discovered
00:24 that some sharks, most notably the great white,
00:26 had some body parts that were warmer
00:28 than the surrounding ocean water.
00:29 Meaning they have been categorized
00:31 as regionally endothermic, or partially warm-blooded.
00:34 Experts long believed this was likely due to their apex
00:37 predator status.
00:38 But now, that same partial warm-bloodedness
00:40 has been observed in the basking shark,
00:42 confounding marine biologists.
00:44 According to the researchers, they
00:46 believe the warm-bloodedness was a trait
00:47 that helped higher food chain creatures achieve their status.
00:50 But add quote, "Now we have found a species that
00:53 grazes on tiny plankton, but also
00:55 shares those rather uncommon regional endotherm features.
00:58 So we might have to adjust our assumptions
01:00 about the advantages of such physiological innovations
01:03 for these animals."
01:04 The researchers dissected a couple of the sharks
01:06 in the hopes of figuring out how it all works,
01:08 discovering compact muscles around the shark's heart.
01:11 Something they say allows them to increase their blood
01:13 pressure and maintain higher temperatures
01:15 in other muscular tissue.
01:18 [Music]
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