Non-Ceph: Sharks in Sperm Whale Stomachs

Discussion in 'The Octopus' Den' started by Sordes, Dec 28, 2007.

  1. Sordes

    Sordes Wonderpus Registered

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    I know sharks are not the actual topic of this forum, but sperm whales comparably often. Sperm whales are reported to consume sharks up to several metres on occasion, and I wanted to know if somebody knows any photos of sharks in sperm whale stomaches, or has perhaps even seen in reality. I am especially interested in the way the stomach of the sperm whale digests the shark carcass, i.e. which parts are digested at first and which remains the longest time more or less intact.
    I suppose some of you have already read much about the contents of sperm whale stomaches, although I suppose most was about cephs. I have read that sometimes deepsea-fish and crustaceens were found in the stomaches of sperm whales, and even the eggs of scates. It would be really interesting to know if you know further details about this topic. I would especially like to know if there are any indications that sperm whales have ever consumed warm-blooded animals like smaller cetaceans or seals. I have never heard about this, and given the fact that even small dolphins swim sometimes near sperm whales, I suppose this normally doesn´t happen.
     
  2. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    I do have a bit to add to this, but don't have the literature on me right now. These are interesting questions!

    I have never seen the bone of any mammal in the stomach of any cetacean (although I know Orca eats seals and attacks larger whales; I've just never worked on a dead Orca before). There is a report (I believe) of shark in the stomach's of NZ sperm whales harpooned in the 60's. I'll dig it out of a box when back at work in a couple of days.
     
  3. Phil

    Phil Colossal Squid Supporter Registered

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  4. Steve O'Shea

    Steve O'Shea Colossal Squid Supporter

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    Thanks for the bump Phil.

    The paper (NZ) that I was thinking of can be found here; just click on the link at the bottom for a full manuscript.

    The abstract is:
    Stomachs of 151 sperm whales were examined at the Tory Channel whaling station in 1963 and 1964. In nine stomachs examined quantitatively there was a 1.69:1 ratio of squid to fish by weight. Some gastroliths were found. The weight of fresh food varied from 12.70 to 105 kg. Two samples of lower mandibles from squids totalling 2,118 specimens were separated into 11 types and subtypes with the help of a previously published key by M. R. Clarke. These types have been designated: Ai, Aii, Aiii; Bi, Bii, Biii; and C, D, E, F, and G. Some beaks (2.36% of the total) could not be grouped into these categories. Onychoteuthid squid made up the bulk of the stomach contents by number and weight. The following squid were identified: Nototodarus sloanei, Histioteuthis cookiana, Architeuthis sp., and Moroteuthis sp. The most common fish in the stomachs were: Polypriori oxygeneios (groper), Genypterus blacodes (ling), Hoplostethus sp., an unidentified eel, and Jordanidia solandri (southern kingfish). Other species recorded included Zeus faber (John Dory), Koinga kirki (spined dogfish), Myctophus humboldti (lantern fish), Echinorhinus cooki, and Echinorhinus sp. or Dalatias sp. Quantitative estimates suggested that commercial species of fish were usually less than 32% of the contents by weight. The feeding habits are discussed.

    The 'shark' to which I referred is Koinga kirki (spined dogfish).

    Many of the names have changed since 1967, and in fact Kat has worked (and published) on some of these beaks, notably those of Moroteuthis . We've come a long way since 1967!
     
  5. Sordes

    Sordes Wonderpus Registered

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    I must have somehow overlooked the replies to this old thread which I started nearly 4 (!) years ago. They are really quite interesting and informative, thank you very much! Especially the report of the megamouth shark relics found in a sperm whale stomach is amazing. It´s really quite frustrating that we still know next to nothing about the actual way in which sperm whales hunt, and of course all the examinations of stomach contents show normally only a random sample of what those whales actually ate during their lives, so a lot of "exceptional ingestions" were most probably never documented.
     

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