In biology, scout bees and ants will return home to "tell" the others where food is to be found, the fact of fertility must be announced to prospective mates from the same species, and the presence of danger must be passed as a warning to others in the group. Such transmission may be chemical, auditory, visual, or tactile whether singly or in combination. There is a new field of research activity termed biosemiotics, and Jesper Hoffmeyer claims that endosymbiosis, self-reference, code duality, the availability of receptors, autopoiesis, and others are the general properties of all living systems. Thomas Sebeok suggests that a similar list of properties for life may coincide with the definition of semiosis, i.e. that the test of whether "something" is alive, is a test to determine whether and how it communicates meaning to another of its kind, i.e., whether it has semiosis. This has been called the Sebeok's Thesis.