1. the principle or practice of unselfish concern for or devotion to the welfare of others (opposed to egoism ).
2. Animal Behavior. behavior by an animal that may be to its disadvantage but that benefits others of its kind, as a warning cry that reveals the location of the caller to a predator.
and this is the opening from wikipedia.
Altruism (pronounced: /?śltru??z?m/) is unselfish concern for the welfare of others. It is a traditional virtue in many cultures, and a core aspect of various religious traditions such as Judaism, Christianity, Islam, Hinduism, Jainism, Buddhism, Confucianism, Sikhism, and many others. This idea was often described as the Golden rule of ethics. Altruism is the opposite of selfishness.
Altruism can be distinguished from feelings of loyalty and duty. Altruism focuses on a motivation to help others or a want to do good without reward, while duty focuses on a moral obligation towards a specific individual (for example, God, a king), a specific organization (for example, a government), or an abstract concept (for example, patriotism etc). Some individuals may feel both altruism and duty, while others may not. Pure altruism is giving without regard to reward or the benefits of recognition and need
Neither of our personal defintiions fit what is given by those sources. What I will say is that your definition of altruism is one that I've never heard before, and by necessity of its defintion is a total loss for the practioner, and probably practiced by no one. So it just seems moot... of course no one is altruistic when altruism is defined as making yourself lose, even in abstract terms. I cannot imagine anyone on earth preaching altruism by that definition, though.
Perhaps, the second dictionary definition fits yours. However, I'm pretty sure I can see the long term benefit in what that hypothetical animal is doing.
EDIT: a number of those definitions would match my own, if we merely qualify that we are talking only about tangible costs and benefits.