How long do they live? Greenland sharks are the longest living vertebrate species known and can live to be 400 years old [1] and possibly longer.  This estimate was based on Greenland sharks that were killed, so it’s not hard to imagine that there are much older ones hiding from whalers.

Where are they found? Their name kind of gives away the surprise. They live in the Arctic oceans of Greenland, Norway, and Iceland and can be found over 7,200 feet deep [2]. See figure 1.

somniosus_microcephalus_distmap
Figure. Range of Greenland sharks.

What do they eat? They feed on smaller fish, which isn’t hard to find because the Greenland shark is quite large [2].

What do they look like? So, Greenland sharks are not only the longest living vertebrates, but they’re one of the largest sharks. They can reach nearly 24 feet long and weigh over 1,700 pounds [2]. See figures 2 and 3.

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Figure 2. This Greenland shark is camera shy.
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Figure 3. This one is not camera shy.

How do they reproduce? Greenland sharks reproduce by sexual reproduction and are ovoviviparous, which means the eggs hatch within the womb and the female gives birth to live young. There is very little known about this species, but they may not reach sexual maturity until 150 years of age [1]. That’s a very long time to wait for sex.

How do scientists know how old they are? Radiocarbon bomb dating of the eye nuclei [1] from 28 dead sharks. So, wait, out of 28 killed sharks, at least one was estimated to be 400 years old or more? Maybe, just maybe, we should stop killing them.

So what are we lacking? Any kind of senescence data, be it reproductive or just general aging characteristics. If there’s a question about aging, then we should be looking to the Greenland shark first to answer it.  There is no nuclear or mitochondrial genome data uploaded to the NCBI website? (Dear editor, you leave that question mark right where it’s at).

Conservation status: Greenland sharks are listed as near threatened on the IUCN Red List of Threatened Species. Unfortunately when they are not being harpooned in the face, they are caught as by catch in gill nets [3]. I wonder how many over 400 year sharks have died as by-catch?

  1. Nielsen, Julius, et al. “Eye lens radiocarbon reveals centuries of longevity in the Greenland shark (Somniosus microcephalus).” Science 353.6300 (2016): 702-704.
  2. Fishbase.org. Greenland shark. http://www.fishbase.org/summary/138 Accessed 10/24/2016
  3. IUCN Red List of Threatened Species. Greenland sharks,. http://www.iucnredlist.org/details/60213/0 Accessed 10/24/2016