GRE Reading Comprehension: JiJing 352-GRE阅读机经352篇 - XX751P54640C1453K

Oscillatory swimming – the alternating of deep dives with forays toward the surface – is among the most common behaviors of large marine animals in the open ocean. The reason most often proposed for this behavior is to warm the body after heat loss during descent into cooler water. Tuna, mako sharks, and white sharks maintain an internal body temperature above that of the surrounding waters thereby improving their muscular efficiency and enabling them to swim with bursts of speed.