Imagine you’re a diabetic and you use a service dog trained to alert you if it senses your blood sugar is falling. These dogs are incredibly useful, because diabetics can lapse into “hypoglycemia unawareness,” where they don’t notice their own oncoming symptoms. The canines do, and they intervene. But sometimes a diabetic shock can emerge so suddenly the human passes out. Then the dog’s in a quandary: How does it go for help? Because dogs can’t talk.