The idea of the sounding animals is as simple as congenial: Take a piece of wood (in this case the wonderful yellowish jackfruit wood), hollow it out and give the whole thing the shape of an animal. Fish, bird, dolphin, frog, and cricket are played by using a wooden stick. The dolphins also produce a sound when played as wind instruments. The sound of these tonewoods is amazingly similar to the sound of real animals. The wood of these instruments was gently treated with vegetable oil and apart from that was left in its natural state. By the way, it has been taken from orchards and not from the rain forest.
The sounding animals, these handy sound transmitters, are the little siblings of the big slit drums as known in Africa, Southeast Asia, Oceania, and Latin America. There tree logs or bamboo canes are hollowed out through one long or two shorter slits. A sound is produced by striking the hollow logs with a hard stick or mallet. Some slit drums are so big and sonorous that they can be heard for long distances. The drums are situated in a horizontal position or hung up vertically. These instruments were (and surely in some places still are) used for acoustic transmission and communication, for example signalizing when there is danger or to announce the beginning of a meeting. They also beat the rhythm for dancing.
Small versions of these mighty instruments are for example our wooden fish. And even for the fish trident wooden pieces were hollowed out through slits. Due to the jackfruit wood and its density and structure, the sounding animals produce a high, clear sound.
Listening to the sounding animals one will be reminded of the sound of tonewoods. But the difference is that one will not have motoric difficulties to find the tone when playing the sounding animals. It is not necessary to balance them in the hand to make them sound as one needs to do with the tonewoods. Our wooden birds, which are attached to a handle, are even easier to play: the corpus of the wooden figure strikes a wooden bowl and sounds just by a slight movement of the arm or wrist.
The sounding animals have a second acoustic property: Most of them have a wooden part which is corrugated. When rubbing a stick or mallet along the notches a sound is produced similar to a guiro, a ratchet, or a scraper. The sound of these instruments is probably most known through Latin American music. A bigger version of scraped idiophones is used in Samba or Cuban music.