Hortense McDuck is a female anthropomorphic duck.
Hortense is Scrooge's sister and the mother of Della and Donald. She married Quackmore Duck some time after 1902. She was known for having a terrible temper, much like her children Donald and Della, to the point that Scrooge named his nervous horse Hortense in allusion to her. In 1930, when Scrooge McDuck, back to Duckburg after many years of travelling around the world, behaved absolutely horribly toward Hortense, this set off the greatest tantrum Hortense had ever had. Dragging her husband, children and sister with her, she left Duckburg, swearing never to see her brother again. Although Scrooge eventually apologized to Matilda, Hortense wasn't there at the time, and likely hasn't forgiven Scrooge yet.