  One of the recent attempts to address the Hubble and $S_8$ tensions is to
consider the Universe started out not as a de Sitter-like spacetime, but rather
anti-de Sitter-like. That is, the Universe underwent an "AdS-to-dS" transition
at some point. We study the possibility that there are two dark energy fluids,
one of which gave rise to the anti-de Sitter-like early Universe. The
interaction is modeled by the Lotka-Volterra equations, commonly used in
population biology. We consider "competition" models that are further
classified as "unfair competition" and "fair competition". The former involves
a quintessence in competition with a phantom, and the second involves two
phantom fluids. Surprisingly, even in the latter scenario it is possible for
the overall dark energy to cross the phantom divide. The latter model also
allows a constant $w$ "AdS-to-dS" transition, thus evading the theorem that
such a dark energy must possess a singular equation of state. We also consider
a "conversion" model in which a phantom fluid still manages to achieve
"AdS-to-dS" transition even if it is being converted into a negative energy
density quintessence. In these models, the energy density of the late time
effective dark energy is related to the coefficient of the quadratic
self-interaction term of the fluids, which is analogous to the resource
capacity in population biology.
