Donald Trump's sons, Donald Jr. and Eric, are under investigation in Zimbabwe to determine if their hunting trip -- which made news when photos of the guys posing with dead animals surfaced last week -- was actually legal. 

The independent Zimbabwe Conservation Task Force said that Trump's sons used a South African safari firm that is not registered in Zimbabwe during their 2011 hunting trip. They reportedly killed an elephant, an endangered leopard, a buffalo, a crocodile and other "big game" animals.

The task force is currently investigating whether license and trophy fees were paid and if the South African firm had been cleared by Zimbabwe wildlife authorities to operate.

Donald Jr. tweeted after the photos became public, saying, "I'm a hunter, for that I make no apologies ... I can assure you it was not wasteful ... the villagers were so happy for the meat which they don't often get to eat. Very grateful."

The father is NOT paying for the actions of his sons ... so says Donald Trump ... who claims all of his "Celebrity Apprentice" sponsors are staying committed to the show after gruesome pics emerged of his kids killing a bunch of animals in Africa.

TMZ broke the story ... Marcus Lemonis -- CEO of Camping World and Good Sam -- is furious about the photos of Don Jr. and Eric Trump posing with their kills ... which included an elephant, kudu and waterbuck. Lemonis told TMZ he vowed not to give another dime to support Trump's show.

Here's the catch ... Good Sam is a major sponsor of a 'Celeb Apprentice' episode scheduled to air next month.

But Trump called in to "TMZ Live" moments ago ... and said despite Lemonis' outrage ... not one sponsor has pulled out ... including Good Sam.

In fact, Trump says the people at Good Sam are THRILLED to be on board ... and told him they are "very much looking forward" to their episode.

Still, Trump once again stated he's NOT a fan of hunting ... but believes his sons were righteous in giving the meat from their kills to local villagers.

Donald Trump's sons' bloody hunting trip in Africa last year didn't just put a dent in the local wildlife population -- it exterminated a lucrative advertising deal on "Celebrity Apprentice" ... by scaring away a big sponsor.

Camping World CEO Marcus Lemonis tells TMZ, the company's TV spots already aired on this season of "Celebrity Apprentice" -- but he insists, "I wouldn't spend another nickel with them."

Marcus adds, "I am totally disgusted by the [hunting] pics I have seen and was surprised to see them ... Money is spent but wow I'm really shocked."

As TMZ previously reported, Donald's sons (Donald Jr. and Eric) went on a hunting safari in Zimbabwe a year ago, killing several animals -- including an elephant, crocodile, kudu, civet cat and waterbuck.

"Celebrity Apprentice" star Lisa Lampanelli is standing firmly behind her TV boss ... telling TMZ she "LOVES" the fact that Donald Trump's sons went on an animal-killing spree in Zimbabwe.

Lampanelli was out in NYC last night ... when we asked about the controversial Trump hunting trip last year ... in which Donald Jr. and Eric killed an elephant, crocodile, waterbuck and more.

Lisa replied, "I love the fact that Mr. Trump and the little other Mr. Trump ... and the other one [approve of hunting] ... I would love it if Ivanka got out there with a bazooka."

She added, "Hunt all you want g*d d*mmit."

As we previously reported, Don Jr. claims he wasn't just killing for fun ... insisting the meat from his kills were used to feed local villagers.

The gruesome photos of Donald Trump's sons posing triumphantly with mutilated animal corpses in Africa isn't going over too well with the animal rights groups ... duh ... and now, they're firing back ... bashing the Trumps as "pitiful" bloodthirsty morons.

TMZ spoke with Jack Carone from In Defense of Animals ... who said, "Would any intelligent person feel moved to murder a magnificent elephant, then further insult and desecrate by hacking off his or her tail as an additional gesture of dominance?"

He added, "Privilege has clearly not bought them the sensitivity or wisdom to view the world as anything but their personal playground, including the imagined entitlement to end the lives of sensitive and social animals for mere amusement."

"This is truly a pitiful testimony to their lack of character and compassion, at the ultimate expense of their innocent fellow Earthlings."

As TMZ previously reported, Donald's sons -- Donald Jr. and Eric -- went on a hunting safari in Zimbabwe a year ago this month, and proudly showed off their trophy kills -- including an elephant, crocodile, kudu, civet cat and waterbuck.

Donald Trump Jr. says he bears NO SHAME for slaughtering a bunch of exotic animals in Africa last year ... claiming all of his kills were used to feed local villagers.

TMZ broke the story ... DTJ is coming under fire for a series of pics which show him posing with his brother in front of several dead animals after a hunt last year -- even showing off a severed elephant tail.

Now, Trump Jr. is DEFENDING the hunt on Twitter ... writing, " I have no shame about [the pics]. I HUNT & EAT game ... I'm a hunter, for that I make no apologies."

He explained, "I can assure you it was not wasteful ... the villagers were so happy for the meat which they don't often get to eat. Very grateful."

"These are not endangered animals as an fyi."

As TMZ previously reported, Donald's sons -- Donald Jr. and Eric -- went on a hunting safari in Zimbabwe a year ago this month, and killed an elephant, crocodile, kudu, civet cat and waterbuck.

Donald Trump's two sons went on a big game hunt in Africa, and the carnage they wrought has triggered outrage by wildlife enthusiasts. 

Donald's sons -- Donald Jr. and Eric -- went on a hunting safari in Zimbabwe a year ago this month, and proudly showed off their trophy kills -- including an elephant, crocodile, kudu, civet cat and water buck. 

In one shot, Donald Jr. is holding a dead elephant's tail in one hand and a knife which appears to have cut off the tail in another.

A wildlife enthusiast's website has just created a YouTube video of the slaughter expressing outrage.

As for Donald Trump, he tells TMZ, "My sons love hunting. They're hunters and they've become good at it.  I am not a believer in hunting and I'm surprised they like it."

Trump added, "I know that anything they did was 100% OK in terms of the hunting community."