Life Lines by Dr. Dolittle

Sponsored by the American Physiological Society


Killer whales scare off sharks

A pair of killer whales, nicknamed ‘Port and Starboard’, has been terrorizing great white sharks. In recent years as many as 8 sharks (possibly more) have succumbed to the pair. Many of the discovered sharks were missing their fatty liver and sometimes their heart. While orca hunting escapades are not particularly newsworthy, the antics of these orcas have attracted the attention of scientists as they are altering the ecosystem. Once […]

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Why sharks should be afraid of leopard seals

Leopard seals in New Zealand have a dangerous appetite. Although the animals were known to eat penguins and other seals, researchers only recently discovered that sharks were on the menu as well, which was really surprising. They made this discovery while analyzing fecal samples collected from more than 100 leopard seals. Leopard seals appear to have joined a growing list of animals (orcas, giant octopus) that dine on what we […]

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Bioaccumulation of metals in sharks

A new study highlights the impact of metal accumulation (cobalt, manganese, nickel, copper, iron and mercury) on the health of twenty individual sharks representing 8 species that were accidentally caught by fisheries in Brazil. Necropsies of the animals showed high levels of metals in the liver, gills and rectal glands. Perhaps not surprisingly, larger animals had more accumulation of the metals in their gills than smaller animals. Higher accumulation in […]

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A whale shark’s superpower: Healing

Da-dum, da-dum…that’s right! Shark week is back!! It starts tonight on Discovery channel. Grab some popcorn, it’s going to be a wild ride! To kick off the week in our own way, I found this interesting study that examined wound healing in whale sharks, the world’s largest fish. These animals often exhibit scars resulting from collisions with boats and new research shows they have impressive wound healing capabilities. In the […]

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We all need to get some shut eye

I have to confess that I have been spending way too much time binge watching shows about sharks during this year’s Shark Week on Discovery Channel. I know I should be getting 7 hours of sleep a night…but could watching just one more show be that bad? Speaking of sleep, I am reminded of a study that I read awhile back examining whether sharks and rays need sleep. This may […]

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It’s shark week!! Let’s talk about the spiny dogfish

I am so excited it is finally Shark Week on Discovery Channel! I look forward to this week every year. In honor of Shark Week, I found a neat study published in the American Journal of Physiology – Regulatory, Integrative and Comparative Physiology examining the rectal gland of the spiny dogfish shark (Squalus acanthias). This gland is very important as it allows the animals to get rid of salt (sodium […]

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Did you know just how interesting shark rectal glands could be?

In case you missed Shark Week this year, I thought I would mention a cool fact about dogfish sharks (Squalus acanthias) that you probably did not learn about. I read an interesting article from a lecture given by Dr. John N Forrest Jr, M.D. that was published in 2016 in Transactions of the American Clinical and Climatological Association. Sharks have a complicated system for regulating water and salt balance in the […]

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