I've mentioned her in other postings, a chocolate point Siamese cat. She vanishes every 6 weeks, replaced by her second person, a very different mix of Psychological Adaptations.
Ordinarily, she bats at my shoe laces and socks when I dress in the morning, sits on my lap when I'm reading on the john, purrs for nearly any situation, and sleeps on my belly or shoulder. She's also a nemesis for the mice in my drafty place. (1)
Her obsessed twin does none of these things. Instead, she yowls for several days (depriving me of sleep as well as herself), doesn't purr, ignores shoe laces and socks, and abandons me during my toilet routines. She is more vocal, eats less, is more active, and has a sleep disturbance. I find small gifts of yellowish fluid around the house. She's quiet only when I grab her on the back of the neck, at which moment she drops her shoulders and elevates her tail ... so high that she will likely snare a lost sparrow or perhaps a low orbit satellite. She's driven in an episode that compares to mania, ignoring her responsibilities in pursuit of a hot shot. The mice party. (2, 3)
NOTES:
1) She's an example of "mismatch" (in the usual sense) when her claws sink into my sneaker lace. She's trapped by the evolved design of her claw when it encounters non-shredding, non-bleeding nylon.
2) She completely swaps her Psychological Adaptations for 5 days. She's not "territorial" in the usual sense; indeed, she's temporarily less aggressive with Sophie who's twice her size and who becomes dominant for several days (perhaps the yowling also bothers her?). I wonder about PA switches in our own species and compare Emmy to the phenomenon of PMS or that of teens in rut (another example of "mismatch" given earlier times when there were no teenagers?).
3) Beck (1988, Love Is Never Enough, NY: Harper) compares love to a manic episode. He's likely very correct. Mania, whether elicited by another human or a quest, might usefully be considered as a switching of Psychological Adaptations, rather than just a mood shift.