Vincent Janik, a marine biologist, vividly recalls watching a pod of dolphins play with seagrass during a field visit to Mikura Island in Japan in 2014.
"They were wrapping the seagrass over their fins and flippers, and passed it on for other dolphins to pick up," Janik, who is also the director of the Scottish Ocean Institute in the United Kingdom, told Mashable.
Most animals, humans included, play. But play in dolphins and some other marine mammals seems especially remarkable. Dolphins are profoundly curious creatures, which drives them to seek activity and stimulation. What's more, the facial anatomy of a dolphin makes it look like they're smiling, and they perform notably playful acts like performing somersaults and leaping around boats.
"Why do dolphins play?" might seem like a simple question. But it's hard to identify the reasons, say marine researchers. What looks like play to humans might be more than just fun to dolphins.
Playing is not always what it seems
Sometimes the highest level of brain development in animals happens during play, and this could be the case for dolphins, Holli Eskelinen, a dolphin researcher and a lecturer at the University of Miami Rosenstiel School of Marine and Atmospheric Science, told Mashable.
Eskelinen once observed a dolphin calf playing with a stick in its mouth. After a couple of months, she found the dolphin learned to use the same stick movement to manipulate and move mangrove seed pods. So, as the dolphins grow, play becomes a way for them to learn what they're capable of, and to stimulate their brains.
"What we observe might be anecdotally classified as play, but it could serve a bigger biological purpose," Eskelinen told Mashable.
"What we observe might be anecdotally classified as play, but it could serve a bigger biological purpose."
على الرغم من أن اللعب هو سلوك مرتبط بالعديد من المخلوقات الأرضية والمائية ، إلا أن الطبيعة الغريبة للدلافين هي التي ربما تفصل سلوكها في اللعب عن سلوك الحيوانات الأخرى ، وفقا لجانيك. على سبيل المثال ، تصبح الدلافين مفتونة عندما تواجه الأسماك المنتفخة ، وهي مخلوق مثير للاهتمام يفجر نفسه مثل الكرة للتهرب من الحيوانات المفترسة. لكن الدلافين تطارد هذه الأسماك ، وأحيانا تلعب الصيد عن طريق تمريرها ذهابا وإيابا.
حتى أن فيلما وثائقيا لهيئة الإذاعة البريطانية (بي بي سي) ادعى أن السم الذي تطلقه الأسماك المنتفخة يسمم الدلافين. ومع ذلك ، لا تزال هذه فرضية. لا توجد أدلة كافية تقريبا لإثبات نظرية التسمم ، وفقا لهيذر هيل ، التي تبحث في سلوك الدلافين وتدرس علم النفس في جامعة سانت ماري ، في تكساس. وقالت: "أعتقد أن البخاخات هي مجرد نوع آخر من الأشياء المثيرة للاهتمام بالنسبة للدلافين للعبث بها".