In just three short lines, this poem sets two scenes side by side: a dolphin eating a sandwich by itself, and the speaker talking with their mother. The title tells us we're at an aquarium, so we can picture a visitor watching the animal while chatting with a parent.
The dolphin's meal is a little odd. Dolphins don't eat sandwiches, so the image is either a playful invention or a sign of how strange and artificial life in a tank can be. The word "alone" stands out. It makes the dolphin seem solitary, maybe a bit sad. Then the last line turns toward the speaker, who is not alone but connected to someone. The word "ma" is warm and casual.
The mood is quiet, gentle, and lightly humorous, with a touch of melancholy. The poem seems to invite a contrast: the captive animal's isolation against the comfort of human company. It doesn't say outright how the speaker feels, but the small, affectionate ending suggests gratitude for that closeness.