 Why was Gertrude continuously screaming?
The Blue Behemoth By LEIGH BRACKETT Shannon's Imperial Circus was a jinxed space-carny leased for a mysterious tour of the inner worlds. It made a one-night pitch on a Venusian swamp-town—to find that death stalked it from the jungle in a tiny ball of flame. With Shannon's Imperial Circus, the Greatest Show in Space, plastered so thick with attachments...." I've wet-nursed Shannon's Imperial Circus around the Triangle for eleven years, and I know. It's lousy, it's mangy, it's broken-down! It has always been my desire to lighten the burden of life for those less fortunate...." "There are many towns along the Venusian frontiers where no entertainment of the— proper sort has been available. It was Gow, our zoo-man—a big, ugly son-of-a-gun from a Terran colony on Mercury. He said, "Boss, Gertrude's actin' up again." "Gertrude be blowed," growled Bucky. "I'm tellin' you, Boss, Gertrude ain't happy. Beamish cleared his throat and said, rather stiffly, "Gertrude?" The only other one on the Triangle belongs to Savitt Brothers, and she's much smaller than Gertrude." Gertrude may be a little creaky, but she's still pretty impressive. I only hoped she wouldn't die on us, because without her we'd have a sicker-looking circus than even I could stand. The extreme rarity of the animal...."
 She was desperate for a mate
 She was cramped in a much too small space.  She missed her family.  She was near starving.  She was desperate for a mate