Life Lines by Dr. Dolittle

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Sharks

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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First known case of zebra shark switching to asexual reproduction

The story begins in 1999 when Leonie, a zebra shark (aka a leopard shark in Australia), was captured from the wild. In 2006 she was transferred to Reef HQ Aquarium in Queensland, Australia where she met her mate. By 2008, she had started laying eggs and the pair had multiple litters of offspring through sexual reproduction. After her mate was removed from the tank to prevent further breeding, she has shared the tank with […]

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