Alopias vulpinus Color varies, Brown to gray brown along the upper body, creamy to white below. Distinctive tail has extremely long upper lobe, with very short lower lobe, as seen right. Eyes are large, but not as large as the Bigeye Thresher, which as huge elongated eyes set high on the head, enabling it to see upwards. Threshers can grow to be 20 ft, 1000 lbs. They prefer cooler surface waters, and feed on all kinds of schooling fish, such as mackerel and bunker. Edible.  
This specimen courtesy of Paul Minning