I can imagine 3 different kinds of communication between individuals:

  1. Communication between individuals of the same species.
  2. Communication between an individual and another from a different species.
  3. Communication between an individual and the same individual at a different time, i. e. some individual "taking notes" or "marks" for later use.

My question is whether there are animals showing (3) but not (1) or (2).

In order to make sure the absence of (1) I stipulate that the individual animal should be capable to live a completely solitary life, which excludes e. g. all mammals from the list of candidates.

Here, the criteria for "communication" are the following:

  • The message is created by a defined action of the animal.

  • The message is an object, separate from the animal's body.

  • The animal is able to interpret the message at a later time, i. e. removal or modification of the message artifact would result in a different behavior.

This question is motivated by the more general question whether the ability to communicate necessitates a social context.

EDIT: In order to make it clearer what communication could be, as suggested by the comments, here are a few examples:

  • territory marking: matches the categories (1), as a signal to rivals and probably (3), as a reminder for the territory owner.
  • alarm call: matches (1) and/or (2)
  • behaviour of the Honeyguides: a typical example of (2)
  • creation of trails: may have a communicative function (e. g. for ants), and is also seen with solitary animals. Is there a case, where the communicative function is predominant and all other criteria are met?

Here is why I think that some classes of species can be excluded:

  • mammals, birds: every individual enjoys parental care, which has a communicative aspect of type (1)
  • plants: may be able to communicate with other plants or animals, but self-communication seems hard to imagine.
  • 1
    $\begingroup$ I think this is an interesting thought, but almost certainly bound to lead to an inconclusive result relative to the motivating question. I think your (3) might be bound up too much in "language" and abstractions that are far higher order than communication more generally. If an animal recognizes a burrow as smelling "like home" and part of that scent includes smells originating from the individual animal, does that count as taking notes or marks? $\endgroup$
    – Bryan Krause
    Commented Nov 20, 2019 at 0:02
  • 2
    $\begingroup$ There's also the problem of identifying a truly solitary animal; you've excluded mammals already, but even non-mammal animals that live alone find a mate, for example, and even animals that don't mate with a particular individual, like cnidarians, communicate with each other to coordinate gamete release. Even unicellular organisms communicate with one another, as do plants. Communication seems to be a much more generic feature of life than the premise in this question seems to recognize. $\endgroup$
    – Bryan Krause
    Commented Nov 20, 2019 at 0:04
  • $\begingroup$ @BryanKrause I think the burrow smelling "like home" would meet the criteria (2) and (3) (if there is the observation), but perhaps not (1) unless the scent is applied by an act like spraying or so. Please note also, that animals that do mate are not excluded, because that fact says nothing about a particular individual that might well live its life alone (I've tried to clarify this by an edit of the question). $\endgroup$ Commented Nov 20, 2019 at 8:00
  • $\begingroup$ It would be cool to have a brief beside the three common types, like "territory marking" "alarm call", it would make the question more accessible. $\endgroup$ Commented Nov 21, 2019 at 9:34


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