MMB precursor felinine is synthesized in the urine from 3-methylbutanol-cysteinylglycine (3-MBCG) by the excreted peptidase cauxin. Felinine then slowly degrades into the volatile MMB. Rats and mice are highly averse to the odor of a cat's urine, but after infection with the parasite Toxoplasma gondii, they are attracted by it, greatly increasing the likelihood of being preyed upon and of infecting the cat. Cat attractants Although they are not produced by the cat themselves, and therefore are not pheromones, cat attractants are also odorants that have an effect on cat behavior. A cat presented with a cat attractant may roll in it, paw at it, or chew on the source of the smell. The effect is usually relatively short, lasting for only a few minutes after which the cats have a refractory period during which the response cannot be elicited. After 30 minutes to two hours, susceptible cats gain interest again. Various volatile chemicals, iridoid terpenes extracted from essential oils, are known to cause these behavioral effects in cats. Cats are known to respond to catnip (Nepeta cataria), Tartarian honeysuckle (Lonicera tatarica), valerian (Valeriana officinalis), and silver vine (Actinidia polygama) to different degrees. The active chemical for catnip and silver vine has been confirmed to be nepetalactone and nepetalactol respectively: they are found in the two plants and synthesized versions of these chemicals trigger similar responses in cats. The active ingredient in Tartarian honeysuckle and valerian may be actinidine, but its effect is yet to be confirmed. References External links Cat behavior Mammalian pheromones