 Leg span is determined by measuring from the tip of the back leg to the tip of the front leg on the opposite side.Some of the largest species of tarantula may weigh over ; the largest of all, the goliath birdeater ("Theraphosa blondi") from Venezuela and Brazil, has been reported to attain a weight of  and a leg-span up to , males being longer and females greater in girth.The fang size of this tarantula reaches a maximum of .