Atlantic White-sided Dolphins get their name from the Greek lagenos which means bottle, rhynchus which means snout or nose and acutus from Latin, which means sharp or pointed and refers to their sharply pointed dorsal fins. These dolphins ranges from 2.53 meters in length. Their pectoral fins are about 30 centimeters in length and their dorsal fins may be up to 50 centimeters in height. Their tail flukes range from 30-60 centimeters across. Females may be considerably smaller than males and average only 182 kilograms. The dorsal region of is black, their flanks are gray and their ventral surface is white. This dolphin’s distinguishing characteristic is the yellow-white patches on their dorsal side and the black rings around their eyes. Their beaks are prominent and contain 30-40 pairs of pointed teeth. Male longevity is about 22 years, female longevity is about 27 years.
Atlantic White-sided Dolphins are found in the temperate and subarctic waters of the north Atlantic ocean from southern Greenland to Massachusetts and from the British Isles to western Norway. Some have been spotted as far south as the Barents Sea, Baltic Sea, the Azores and the Adriatic Sea. Atlantic White-sided Dolphins inhabit open water that is typically 40-270 meters in depth over continental shelves and is rarely seen from shore. This species is typically found in waters with low-salinity & surface temperatures between 6-20 °C as they migrate seasonally along continental slopes. Atlantic White-sided Dolphins feed on shrimp, smelt, hake, squid and herring. Their major predators are Killer Whales and sharks. Males are sexually mature when they are between 2.1-2.4 meters in length, females between 1.94-2.22 meters or about 6-12 years of age. Calves are usually born in June and July following a gestation period of about 10 months and measure 1.1-1.2 meters in length and average about 25 kilograms. Females nurse for about 18 months and give birth every 2-3 years.