Why can't dogs eat chocolate?

The simple answer to this, of course, is that it is poisonous to them. But that doesn't really explain why, does it? Apparently, chocolate contains something called theobromine (similar to caffeine), which is an alkaloid that dogs cannot metabolize quickly. Theobromine releases epinephrine (better known as adrenaline), which causes hearts to race and can induce cardiac arrhythmia (irregular beating of the heart). Thus, if a dog eats a large amount of chocolate, the theobromine builds up (as the dog's stomach cannot digest it quickly enough) and reaches a toxic level of concentration.

Of course, the severity of chocolate poisoning depends on the size and weight of the dog, but it is often lethal, especially if the dog consumes quantities that are probably unhealthy for humans. Chocolate poisoning can cause vomiting, diarrhea, excessive urination, and hyperactivity, which is closely followed by depression, seizures, coma, and, ultimately, death. So keep Fido away from chocolate!

What’s the deal with dog years, anyway?

Interestingly enough, and contrary to common belief, the conversion factor is not simply seven human years to one dog year. That is simply an approximation based on the fact that our canine friends mature about seven times as quickly as humans do. In fact, the first year of a dog’s life is equal to fifteen human years. After that, however, aging slows incredibly; for example, a 5-year-old dog may be compared to a 35-year-old human. A chart (courtesy of Cindy’s Poodles) detailing the approximate correlation between human and dog years:

Dog years = Human years

1 = 15
2 = 24
3 = 28
4 = 32
5 = 36
6 = 40
7 = 44
8 = 48
9 = 52
10 = 56
11 = 60
12 = 64

[Exit Orpheum.]

[Edit: an uncharacteristically stupid error corrected.]