Judging from her size, Rosie appears to be right around eight weeks old - just old enough to have left her mother - so it's likely that her nuzzling up against Lilo is actually an attempt to find a nipple and therefore some milk! It's not so surprising that a baby animal would seek out comfort and care from another unthreatening animal regardless of species, but it always seems a bit surprising when an adult animal "adopts" a baby from another species like Lilo has. 

Jenny Holland, a National Geographic contributing writer and author of the book Unlikely Friendships, says that this type of bonding between animals of different species really isn't that uncommon, especially in domestic animals. Part of the reason might be due to the basic rules of instinct; Holland explains, "Instinctively animals take care of young to help them survive and therefore pass on the family DNA...So I think there's some hard wiring in there that leads them to offer care to another animal in need." Applied animal behaviorist Jill Goldman offers another perspective, pointing out that it may have something to do with a desire to form mutually beneficial relationships, though this seems far more likely to be the case for wild animals that find protection and strength in numbers. 

Regardless of what the specific mechanism is that made Lilo immediately fall into the role of mother, her reaction to baby Rosie is just wildly adorable. Watch the video below to see just how wonderful Lilo was in helping Rosie feel comfortable and safe; it's probably the cutest thing you'll see all day.