May 19, 2010

Brutus' Necropsy

Dean Cluff necropsied Brutus last week and learned that:

1. The hole in his rib cage was the result of a scavenger, probably a raven.

2. The carcass was emaciated, with no fat even in the femur bone marrow. Fat there is the last to be used, so when it is gone, the animal dies.

Thus we conclude that Brutus died of starvation. Why he starved is unknown. The last time we know he was with the pack was March 29 (see April 29 blog). He could have been in marginal condition then, which we could not have detected from photos.

He traveled straight-line distances of 110.5 miles (176.8 km), or an average of 9.2 mi (14.7 km)/12-hr period from March 29 to April 4 when he then remained in a single location for at least 36 hr. We presume this indicates a kill. After leaving that on April 6, he traveled a straight-line distance of 70.9 miles (113.4 km), or an average of 5.9 mi (9.4 km)/12-hr period before reaching the location where he died, sometime about April 13-15.

A rough and very preliminary examination of all Brutus' location data from October on suggests that the pack's rate of kill was similar from October through January. However in February it dropped by 45%, and in March by 65% from the Oct.-January period. Had the pack killed most of the vulnerable muskoxen by then?

Was Brutus' kicked out of the pack after the last kill on April 5-6? Was he too old or weak then to compete for food at that kill? Was the kill only a muskox calf from last year that had too little food on it to feed the whole pack? Wolves can eat 22 pounds (10 kg) at a sitting, so a calf would not fully feed all 20 wolves.

Brutus' death raises this and many other questions.

Most of them will remain unanswered, but they help feed our motivation to learn more about this pack and its ecology and behavior. Hopefully this summer we will collar more wolves and thus continue to discover much more. We also will begin analyzing the data from Brutus. So, please check back with us periodically.

Thanks for your continuing interest.



  1. I've been following this blog for a while and thank you for posting the results of the necropsy.

    This blog gives me such a unique insight into the secret lives of wolves. I hope you can continue to track and study and report!

  2. AnonymousMay 19, 2010

    How interesting,thanks for keeping us updated.

    I look forward to your next trip out there and the data analysis.

  3. Thank you for sharing all the information on Brutus. I was surprised by the results, was actually hoping he died in action but starvation, too is a harsh reality of a wolfish life; as is being kicked out due to age/weakness. Looking forward to all you care to share! BTW...are there more pics of Brutus to be found or more info on his personality, etc.?

  4. This is very sad, but it makes me feel better to know that he wasn't gored by a horn. I feel bad that he had to die at all, but you are right when you say that he lived a long, good life. I didn't know him, but I felt like I did, and any death is a tragedy. However, I guess that we can now watch the pack to see if a new hierarchy results. I am going to believe that he wasn't pushed out of the pack, but I wonder if that's what happened. Thanks for the update, I enjoy following the life of the wolves.

  5. cgettig,
    There are more images in the 2006 portion of the blog.


  6. So sorry about the lost of Brutus :-(

    Too, I look forward to your next trip out there!!

  7. Piera FumagalliJune 15, 2010

    Thank you for all of your interesting research on wolves. I'm sure you considered this possibility for the cause of Brutus' death, but I'm wondering why you didn't mention it. In your (Dave Mech's) book (Wolves: Behavior, Ecology and Conservation on page 123)there is this: "Even wolves may be challenged by the frozen carcasses of prey. In January and February 1994, daily minimum temperatures on Isle Royale were rarely above -18C (0F) for 5 weeks. During this period, an elderly breeding pair in one pack, both 8-9 years old and with well-worn teeth, died of starvation, even though their pack was able to kill moose."
    Is it possible that Brutus was not kicked out of the pack but was unable to eat enough with his worn teeth due to frozen carcasses? You showed pictures of Brutus' teeth, which were in fact well-worn.

  8. Piera,
    Good point, and a possibility. However, freshly killed prey remains thawed for several hours, even at such cold temps. But maybe Brutus couldn't get
    in on the kills while still fresh because possibly he was ousted from the pack.