Do Animals Know When You're Sad?

Do Animals Know When You're Sad? Your tears are odorless and still drop a man's testosterone. Eighteen dogs walked past their own owner to reach a crying stranger. A rat frees a trapped cagemate and gives up chocolate to do it. Cats read their owner's smile and nobody else's. So does an animal actually know you're sad — or only that you've changed? Key sources: Albuquerque et al. (2016) · Sobin & Sackeim (1997) · Gelstein et al. (2011), Science · D'Aniello et al. (2018) · Custance & Mayer (2012) · Sanford et al. (2018) · Langford et al. (2006), Science · Ben-Ami Bartal et al. (2011), Science · Burkett et al. (2016), Science · Fraser & Bugnyar (2010) · de Waal & van Roosmalen (1979) · Galvan & Vonk (2016) · Sundman et al. (2019) · Mech (1966). Full citations in the comments.