Titi monkeys are pair-bonding monkeys. They engage in affiliative behaviors like the one depicted here: tail twining! Titi monkeys tail twine during the day in order to maintain contact with their partner, similar to hand-holding in humans. At night, titi monkeys tail twine to maintain proximity and help each other balance while sleeping! Happy Valentine’s Day!

[Photo by Alexander Baxter, caption by Allison Lau]

Bales, K.L., del Razo, R.A., Conklin, Q.A., Hartman, S., Mayer, H.S., Rogers, F.D., Simmons, T.C., Smith, L.K., Williams, A., Williams, D.R. and Witczak, L.R., 2017. Focus: comparative medicine: Titi monkeys as a novel non-human primate model for the neurobiology of pair bonding. The Yale journal of biology and medicine, 90(3), p.373.