Studies of wild dolphins have shown that some are
§1. As his feet splash through the warm waters of a huge outdoor pool at Dolphin Cove in the Florida Keys, USA, tenyear-old Jamie has a delighted expression on his face. He suffers from a disability which means he has difficulty communicating with the rest of the world, but the presence of playful dolphins elicits attention and squeals of pleasure. His parents are happy, too. 'In the past, he wouldn't even touch anything solid, and now he's grabbing hold of the dolphin's fin', says May, Jamie's mother. 'It's opening a new world for him.'
§2. The captive dolphins are part of the Dolphin Human Therapy programme, established by Dr David Nathanson, who uses dolphins to help children with mental and physical disabilities. The dolphins are not treated as miracle healers. Instead, the possibility of touching their grey-suede skin or even having a swim with a dolphin is a reward that encourages children like Jamie to respond to their teachers, who sit with the children at the water's edge. The sessions start with the teacher encouraging the child to motion 'hello' to a dolphin, which responds with a shake of its head or fin. The child is offered another chance to play with the dolphin if he or she works hard during the session.
§3. Adults too are attracted to swimming with captive dolphins as well. At a theme park near Orlando, people pay to have a 30-minute swim with them. It is a deeply memorable experience. When a swimmer slides into water alongside a dolphin they can actually feel their skin tingling as the dolphin scans them with sonar (гидролокатор). Then with a flip of their powerful tails, the dolphins are off, gliding around effortlessly, clearly observing their human visitors.
§4. Anyone tempted to swim with wild dolphins, however, should be careful. They can have a vicious streak. Male dolphins will sometimes kill baby dolphins, to attract the attention of females. They have also been filmed killing small porpoises (animals similar to dolphins), probably mistaking them for baby dolphins.
§5. Scientists have discovered that dolphins 'talk' to each other, through a form of whistling. The animals practise 'whistle matching', which is when one dolphin whistles and another repeats the sound within three seconds.
§6. Back at Dolphin Cove, the dolphins' contribution to the children's progress is acknowledged. 'I think dolphins are incredible,' says Jeffrey Bicknell, who works with the children. 'I've seen them look at a child and observe what the problem is, and change their behaviour according to the nature of the problem. They are more dominant with some children, more patient with others.'
2) more unfriendly than they used to be.
3) willing to swim with humans.
Правильный ответ 1. Во фрагменте 4 мы читаем, что люди, решившие с ними плавать "should be careful", дальше это поясняется, почему: "Male dolphins will sometimes kill baby dolphins". Т.е. дельфины, живущие в дикой природе, проявляют агрессию к другим дельфинам.
Правильный ответ указан под номером 1.