It’s the latter: Popo, the Hippo. 
河馬 【かば】 (n) hippopotamus
Notice the の as it makes it easier to separate the name from the noun. But, also as @Racing-Boat noted, the name itself is in katakana, while the word hippo is in hiragana.
As a sidenote, about DeepL. I’d rather go to a dictionary for inquires like this. It’s easy to search both the English word and Kaba on Jisho, to find the Japanese word, along with related words.