At age 39, Pablo Escobar was a billionaire. The head of the Medellin drug cartel in Colombia, per Forbes, had an estimated net worth of around $3 billion. All of these earnings were ill-gotten — his cartel controlled roughly three-quarters of the global cocaine trade, and Escobar was a man wanted by both U.S. and Colombia officials. This combination of wealth and crime created a strange problem for Escobar: he simply had too much cash.

Which was good news for the rats.

Escobar was wary of bankers — and vice versa. Escobar couldn’t risk putting too much money into any one bank, given that he had no legal recourse if they simply “lost” his deposits. Of course, he had other ways of exacting revenge, so this fear can easily be overstated. Bankers, however, had much more reasonable fears. If Escobar were ever convicted of a crime, those funds could be frozen or taken back by authorities. Or even worse, an aggressive prosecutor could have lumped the banker in with Escobar, as some sort of accomplice or co-conspirator. After all, it’s not like people in Colombia regularly walk into the bank to make six-figure deposits using American currency.

Escobar spent money in droves. In his community, he had a reputation of being a Robin Hood type, using his drug money to build schools, hospitals, churches and ball fields. He also spent a lot on frivolous items for himself, including a 5,500-acre estate replete with an airstrip, a dozen large statues of dinosaurs, and a wild animal preserve of sorts. Escobar owned multiple giraffes, elephants, zebras, and even four hippopotamuses.

But in the end, he could not spend it fast enough. So he rolled up wads of $100 bills and stored them in a warehouse. According to the book “The Accountant’s Story,” the memoir of Roberto Escobar — Pablo’s brother and the cartel’s top accountant — Escobar (Pablo) had so much cash on hand that he was spending $2,500 a month on rubber bands, necessary to bind them together. To those of us who are not kingpins of the cocaine trade, spending $30,000 annually on rubber bands seems like a huge expense. But for Escobar, it was a rounding error.

In fact, Escobar’s warehouse of cash had a much bigger problem: rats. They’d enter the warehouse at night and feast on the portraits of Benjamin Franklin captured within each rubber band. Over the course of his criminal career, Escobar lost an estimated 10% of his wealth into the stomach of these rodents.

Bonus fact : Escobar died in a firefight in 1993, a day after turning 44. His estate was ransacked soon thereafter by treasure seekers and most of the other stuff was seized by authorities. But the four hippos remained — they were too cumbersome to move. Since then, they’ve multiplied in number, reaching 30 as recently as July of 2011, and are generally considered a menace.

From the Archives: Hippo in the Sun: Hippos spend a lot of time in the sun, but rarely get sunburns. Here’s why.

Related: “The Accountant’s Story” by Roberto Escobar. 3.5 stars on 21 reviews, available on Kindle.