WASHINGTON — President Donald Trump asked his defense secretary to explain whether seals and Navy SEALs were the same thing during a recent national security briefing, sources confirmed today.

Defense Secretary Jim Mattis at one point had to mime a special operator raising a rifle while rising out of the water in contrast to a picture of a lovable marine mammal that lives in the ocean, officials said. The president's question about the differences between SEALs and seals came just days after he reportedly asked Microsoft founder Bill Gates whether HPV and HIV were the same.

Mattis declined to comment on a private conversation with the president, but a source familiar with the matter said the secretary told Trump that SEALs are elite special operators familiar with maritime operations and are superior swimmers, in contrast to seals, which are animals that live in the ocean.

"Navy SEALs did indeed kill Osama bin Laden, Mr. President," Mattis said, according to one source. "But there were no seals there on the raid," he added, further confusing Trump.

Mattis finally resolved the miscommunication by mentioning that seals lack opposable thumbs, making it impossible for them to write books about the bin Laden raid after the fact.

Although Pentagon sources say the president now understands the difference between the two, one senior White House official told reporters that Trump was surprised that no one placed a giant aquarium tank on stage in the East Room of the White House ahead of a Thursday ceremony to present the Medal of Honor to Navy SEAL Chief Britt Slabinski.