Elderly cockroaches get arthritis and become confused and prone to wandering.
Case Western Reserve University researchers reported in the Journal of Experimental Biology that as the roach's life wanes between 60-65 weeks after the onset of adulthood, and the cockroach slows down, experiences stiff joints and has problems climbing and a decreased spontaneous fleeing response. Death comes shortly after the onset of these movement problems.
(via Ambiguous)