Relationships can be difficult. No matter how long you’ve been with someone, there will always be tough times ahead. However, some people have found a way to make monogamy work. And like these humans, there are certain animal species that prefer to have only one partner thoughout their entire lives as well. According to the National Science Foundation, about 5% of mammals are monogamous. And mammals aren’t the only ones. There are monogamous birds and reptiles as well. So if you believe in love, scroll through the following pictures and check out the animals that have found a way to make their love last.