By Mmo iwdg - https://commons.wikimedia.org/w/index.php?curid=10262057
By Chris_huh - https://commons.wikimedia.org/w/index.php?curid=2159298
They are abundant in the world, with an estimated population of about 6 million worldwide. Their length is between 1.9 and 2.5 m (6.2 and 8.2 ft) and weigh between 80–235 kg (176–518 lb).
They live in groups of 20-30, but groups of hundreds and even thousands of dolphins have been observed. In rare events, groups will come together to form mega-pods which can consist of over 10,000 dolphins.
There is evidence that common dolphins use signature whistles, similar to that of the bottlenose dolphin. As many as 29 common dolphin signature whistle types were detected in South Africa.
Sources:
(*) https://en.wikipedia.org/wiki/Common_dolphin(*) https://www.inaturalist.org/taxa/41526-Delphinus-delphis
(*) https://animalia.bio/short-beaked-common-dolphin