（一）食性
鱷龜是以動物性餌料為主的雜食動物，食譜范圍廣。在野生條件下，剛孵出的稚鱷龜、幼鱷龜主要攝食大型浮游動物（枝角類、橈足類）、蝦的搔狀幼體、蝦苗、魚苗、水生昆蟲及水絲叫等底棲動物，也攝食少量植物碎屑。成鱷龜則攝食魚、蝦、蛙、螺、蚌、蛇等，也攝食一些植物性餌料，如野果、植物莖葉、瓜果蔬菜、水草和各種藻類等。在人工養殖的情況下，食譜更廣，常以貝類、魚糜、豬肉、牛肉、動物內臟、蠅蛆、蛆叫、黃粉蟲以及粕餅類、麥類、大豆等為食，并搭配南瓜、蘋果、菜葉等。工廠化養鱷龜則飼以人工全價配合飼料。鱷龜作為寵物飼養時要注意切勿過度喂食，以免龜過分肥胖。
（二）攝食方式
鱷龜(gui)(gui)主要(yao)在水(shui)中覓獵食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)，當(dang)夜深人(ren)靜時(shi)，則游出水(shui)面，爬向岸邊(bian)覓食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)，因(yin)此(ci)喂(wei)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)時(shi)應將(jiang)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)投人(ren)水(shui)中或放(fang)在水(shui)邊(bian)。鱷龜(gui)(gui)在攝食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)過程中并不主動出擊，只靜候食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)到達或潛伏在水(shui)底踢步潛行，待(dai)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)接近時(shi)，即伸頸張嘴吞食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)，因(yin)此(ci)鱷龜(gui)(gui)的(de)(de)攝食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)方式(shi)為吞食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)。鱷龜(gui)(gui)主要(yao)利(li)用其銳利(li)的(de)(de)爪及伸縮敏捷、轉動自如的(de)(de)頭頸獵取食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)，并將(jiang)獵獲的(de)(de)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)吞人(ren)口中，經上下(xia)領特化(hua)的(de)(de)角質詠壓(ya)碎，再(zai)由(you)下(xia)領前緣與口角附近的(de)(de)唾(tuo)腺(xian)分泌唾(tuo)液使食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)潤滑，以便吞咽。鱷龜(gui)(gui)生(sheng)性(xing)貪食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)，在密養(yang)條件(jian)下(xia)，當(dang)缺乏(fa)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)時(shi)會(hui)互相(xiang)(xiang)撕咬爭(zheng)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)。在食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)不足或飼養(yang)密度過大(da)或大(da)小鱷龜(gui)(gui)混養(yang)時(shi)，其同類殘食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)現象相(xiang)(xiang)當(dang)嚴重。鱷龜(gui)(gui)的(de)(de)耐饑能力很強，當(dang)食(shi)(shi)(shi)(shi)(shi)(shi)(shi)(shi)物(wu)(wu)缺乏(fa)時(shi)，在相(xiang)(xiang)當(dang)長(chang)的(de)(de)一段時(shi)間內不會(hui)死亡，但生(sheng)長(chang)停止，體(ti)質變弱。