This question just appeared on the DNR website. I thought you might find it interesting. Has anyone seen any bear showing signs of chocolate poisoning? Do many hunters use chocolate as bait? We haven't seen any cases in the lab. I was just wondering how prevalent it is.
Here's the question:
I was planning on baiting bears with chocolate but I was told that it would kill a bear like it will a dog, is this true?
This is my answer:
Yes, there is some truth to that. Many species are susceptible to chocolate poisoning. Last fall, 2002, we diagnosed 2 deaths in raccoons due to chocolate poisoning. They were adult raccoons and were found dead on a bear bait pile. But, we have never diagnosed a bear in Michigan with chocolate poisoning.
Theobomine is the compound in chocolate responsible for the toxicity. It is found in chocolate, baker's chocolate, tea, and cola products. In dogs, signs of toxicity can occur with the ingestion of 0.4 ounces of milk chocolate/kg body wt. The lethal dose is reported in dogs to be 250 and 500 mg/kg body weight.
Using these figures for dogs, a 200 (90.7 kg) pound bear might show signs of toxicity if it ate only 36 ounces of milk chocolate, a little over 2 pounds. Early clinical signs include excitement, agitation, nervousness (not things you want to see in a large bear!), increased thirst and vomiting. Death can occur after early signs due to heart arrhythmias. Severely affected animals can have muscle spasms and seizures followed by coma.
Again using the figures for dogs, a 200 pound bear would need to eat 23 to 47 pounds of milk chocolate to die of theobromine poisoning.
The Merck Veterinary Manual is available free on the web at:
Portions of the above information was taken from the Merck's section on chocolate poisoning.
And this is a reply from MSU wildlife veterinarian, Jim Sikarski:
I don't know of any cases of chocolate poisoning in bears, but it is quite common in dogs and for all practical purposes, bears are just big dogs. The fact that they are so big means that it would take a lot of chocolate to cause toxicity, but 5-10 pounds is not likely to cause a problem in a 2-300 pound bear. A big dog (75-80#) can get away with eating 4-5 #s of milk chocolate, but unsweetened chocolate is about 10 times more toxic. I'm thinking a 2-300 pound bear could eat 15-20 pounds of milk chocolate and not die, but might be seizuring and easier to shoot ( or hyper responsive to stimulae and dangerous and unpredictable!) Smaller bears certainly might eat enough at a bait site and depending on the amount out there, any bear could (would in the fall) eat enough to have a problem.