Here's a wonderful video that'll make your day. Watch Champ, a wild stallion, rescue a young filly in raging water.
Many nonhuman animals form close and enduring friendships and often help others in need (see also). Recently I wrote about bonobos who help others who are caught in traps.
Compassion and empathy are widespread among many different animals (including rats, mice, and chickens) and the rescue of one horse horse by another horse is not at all surprising but infrequently seen. How lucky we are to witness these sorts of social encounters. Stay tuned for more "surprises" about the amazing cognitive, emotional, and moral lives of other animals.