Washoe was a chimp who was taught sign language.
One of Washoe’s caretakers was pregnant and missed work for many weeks after she miscarried. Roger Fouts recounts the following situation:
"People who should be there for her and aren’t are often given the cold shoulder—her way of informing them that she’s miffed at them. Washoe greeted Kat [the caretaker] in just this way when she finally returned to work with the chimps. Kat made her apologies to Washoe, then decided to tell her the truth, signing "MY BABY DIED." Washoe stared at her, then looked down. She finally peered into Kat’s eyes again and carefully signed "CRY", touching her cheek and drawing her finger down the path a tear would make on a human (Chimpanzees don’t shed tears). Kat later remarked that one sign told her more about Washoe and her mental capabilities than all her longer, grammatically perfect sentences." 
Washoe herself lost two children; one baby died shortly after birth of a heart defect, the other baby, Sequoyah, died of a staph infection at two months of age.
more about Washoe:
after the death of her children, researchers were determined to have Washoe raise a baby and brought in a ten month chimpanzee named Loulis. one of the caretakers went to Washoe’s enclosure and signed “i have a baby for you.” Washoe became incredibly excited, yelling and swaying from side to side, signing “baby” over and over again. then she signed “my baby.”
the caretaker came back with Loulis, and Washoe’s excitement disappeared entirely. she refused to pick Loulis up, instead signing “baby” apathetically; it was clear that the baby she thought she was getting was going to be Sequoyah. eventually Washoe did approach Loulis, and by the next day the two had bonded and from then on she was utterly devoted to him.
*information shamelessly paraphrased from When Elephants Weep by Jeffrey Masson.
Even more interestingly, after Washoe and Loulis bonded, she started teaching him American Sign Language the same way that human parents teach their children language. It only took Loulis eight days to learn his first sign from Washoe, and aside from the seven that his human handlers learned around him, he learned to speak in ASL just as fluently as Washoe and was able to communicate with humans in the same way she could.