Usually, clams are pacifists. If one closes on your finger, it will likely quickly reopen because

1. It's dangerous to be stuck on a predator with tissue exposed
2. It takes energy to maintain closure
3. The clam risks breaking its weak shell margin

However, there have been confirmed cases of birds being injured when bivalves attach to their beaks, feet, or feathers! Some bivalve species may even use this as a method to disperse to new habitats! Pigs might not fly, but clams can! #clamFacts